4GB . What you describes is a bit what Transmeta tried to do with their code morphing software (which was dynamically translating x86 "bytecode" into Transmeta internal machine code). CPU hardware has the advantage of dynamic scheduling, and I don't think there is an example of statically scheduled processor which is competitive on pure performance for single thread with OOO. Does your organization need a developer evangelist? The question can be rephrased as: "Given a hardware platform that is destined to be a failure, why (1) didn't (2) couldn't the compiler writers make a heroic effort to redeem it?". When you could really properly fill it, which often involved either PGO or hand-coding, it did great - but a lot of the time, performance from compilers was really just uninspiring. Why did the Intel Itanium microprocessors fail? Modern x86 processors, with the exception of Intel Atom (pre Silvermont) and I believe AMD E-3**/4**, are all out-of-order processors. The compilers had to patch up late-to-detect flaws of CPU implementations, and some of the performance edge was lost to hard to predict mistakes. Why do new language versions typically use an early compiler version for the bootstrap compiler? (This was before Thumb2, et al - RISC still meant fixed-length rigidity.) The second key difference is that out-of-order processors determine these schedules dynamically (i.e., each dynamic instruction is scheduled independently; the VLIW compiler operates on static instructions). With the Alpha chip design team at AMD, the Athlon already showed their ability to create competitive performance and x86-64 takes away the 64 bit advantage. In a CPU like the Itanium or the SPARC with 200+ registers, this can be rather slow. At same generation and fab technology, it would have been running faster and capped all the same but a bit higher, with maybe other doors to open to push Moore's law. IPF didn't make it easy to generate great code, and it was unforgiving when code wasn't great. @rwong, I made a TLDR of what I consider my main points. Of course, technical reasons aren’t the only reason why Itanium failed. It's its place in time and market forces. Aleksandr, there are multiple parts to the answer. I think Itanium still has its market - high end systems and HP blade servers. Itanium instructions were, by nature, not especially dense - a 128-bit bundle contained three operations and a 5-bit template field, which described the operations in the bundle, and whether they could all issue together. David W. Hess (dwhess@banishedsouls.org) on 7/6/09 wrote: >My observations at the time were that the 386 performance increase over the 286 That pretty much nails the problem. Part of it were technical reasons, such as that the initial product was too large/expensive and not fast enough to be competitive, especially not compared to AMD's x64. AMD's move was so successful that Intel (and Via) were essentially forced to adopt the x86-64 architecture. The AMD Opteron. What do do at this juncture? What are multiplexed and non-multiplexed address pins? Working with WSUS, I sometimes find myself declining the exact same type of updates each month after Patch Tuesday. “The operation was a success, although the patient died,” goes the old surgeon’s joke. Catastrophe hits in 1999 October when AMD announces the x86-64. Demonstrating how slowly markets move, it has taken years for applications to catch up to 64-bit, multi-threaded programming, and even now 4GB RAM is standard on low-end PCs. It seems to me that if the explicit parallelism in EPIC was difficult for compiler vendors to implement... why put that burden on them in the first place? AFAIK, Intel EPIC failed because compilation for EPIC is really hard, and also because when compiler technology slowly and gradually improved, other competitors where also able to improve their compiler (e.g. rev 2020.12.2.38097, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide. To help explain why it is not always possible to find enough work to fill up the stalls, here is how one could visualize it. The compilers became quite good at it, especially when using PGO profiling (I worked at HP and HP's compiler tended to outperform Intel's). So you have to know how and why it works at least a little. With Itanium due in 1999 (and full of hype at this point), SGI canned the "Beast" project and decided to migrate. Moderators: NeilBlanchard , Ralf Hutter , sthayashi , Lawrence Lee Is it worth getting a mortgage with early repayment or an offset mortgage? site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. As Robert Munn pointed out -- it was the lack of backward compatibility that killed the Itanium ( and many other "new" technologies). It is an example of failure to apply the 80-20 rule of optimization: Optimizing things that are already fast will not meaningfully improve overall performance, unless the slower things are also being optimized. Why?? Why was the Itanium processor difficult to write a compiler for? In response to answer by Basile Starynkevitch. 11 years later he's still basically right: per-thread performance is still very important for most non-server software, and something that CPU vendors focus on because many cores is no substitute. your coworkers to find and share information. There were a number of reasons why Itanium (as it became known in 1999) failed to live up to its promise. And as several explained, EPIC compilation is really hard. Why Itanium Failed To Be Adopted Widely. Do MEMS accelerometers have a lower frequency limit? by SunFan on Monday February 28, 2005 @01:50PM and attached to IBM to Drop Itanium. Many compiler writers don't see it this way - they always liked the fact that Itanium gives them more to do, puts them back in control, etc. Where did the concept of a (fantasy-style) "dungeon" originate? PSE avoids this layer by instead using 4 reserved bits in the page tables to specify the high bits. Regardless of the qualitative differences between the architectures, IA64 could not overcome the momentum of its own x86 platform once AMD added the x86-64 extensions. PowerPC is only surviving in the embedded space. The issue with EPIC is that it can use only the parallelism that a compiler can find, and extracting that parallelism is hard. IPF was meant to be backwards compatible, but once AMD64 launched it became moot, the battle was lost and I believe the X86 hardware in the CPU was just stripped to retarget as a server CPU. What is the easiest way to embed a bluetooth to any device? As I recall at the time, the issue was not just the particulars of IA64, it was the competition with AMD's x86-64 instruction set. Recent SPARCs devote a fair amount of chip area to optimizing this, ... 32bit opcodes but not more! In other words, it is not always possible (within the confines of software logic) to calculate the address up front, or to find enough work to do to fill up the stalls between these three steps. most software companies would have bitten the bullet and made the effort. What killed Itanium was shipment delays that opened the door for AMD64 to step in before software vendors commited to migrate to IA64 for 64 bit apps. So fast chip with a reasonable OS but a very limited set of software available, therefore not many people bought it, therefore not many software companies provided products for it. The main problem is that non-deterministic memory latency means that whatever "instruction pairing" one has encoded for the VLIW/EPIC processor will end up being stalled by memory access. The compiler aspect was not the only aspect which was overly ambitious. Why Itanium’s imminent demise increases the risks with OpenVMS applications by Paul Holland , VP of Operations, Advanced The OpenVMS operating system was developed back in the 1970s, and it continues to drive numerous mission-critical business systems worldwide. Working with WSUS, I sometimes find myself declining the exact same type of updates each month after Patch Tuesday. Solamente algunos miles de los Itanium se vendieron, debido a la disponibilidad limitada causada por baja producción, relativamente pobre rendimiento y alto coste. The Itanium chip might have given Intel much grief, but it is through difficult and sometimes failed projects that companies learn. Optimizing instructions that do not stall (register-only, arithmetic) will not help with the performance issues caused by instructions that are very likely to stall (memory access). Why did the Intel Itanium microprocessors fail? site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. Early chips were atrocious. Windows Server 2008 R2 with Service Pack 1 (SP1) includes previously released updates for Windows Server 2008 R2. @Nubok: Not correct - there were two mechanisms, PAE & PSE-36, to gain access to memory >4GB on 32-bit machines and none involved segment descriptors at all. So how is this different from VLIW? Had AMD never come up with x86-64, I'm sure Intel would have been happy to have everyone who wanted to jump to 4GB+ RAM pay a hefty premium for years for that privilege. And downvoted. It's not like a good, well-understood solution to this problem didn't already exist: put that burden on Intel instead and give the compiler-writers a simpler target. Compilers have decent success at extracting instruction-level parallelism, as are modern CPU hardware. Complexity of compilers? VLIW machines can and do execute multiple bundles at once (if they don't conflict). They started a visionary research project using personnel and IP from two notable VLIW companies in the 80s (Cydrome and Multiflow -- the Multiflow Trace is btw the negative answer posed in the title, it was a successful VLIW compiler), this was the Precision Architecture Wide-Word. You are probably too young to know the entire story. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. Was Itanium a deliberate attempt to make a premium platform and pull the rug out from under AMD, VIA, etc.? The big problem is that when it asked me to run root.sh on both node 1 & 2 it returns Checking to see if Oracle CRS stack is already configured Setting the permissions on OCR backup directory Setting up NS directories Failed to upgrade Oracle Cluster Registry configuration. Leaving optimization to the compiler was a good idea. I guess that their management underestimated the efforts needed to make a compiler. For example, if a processor has all of the following: Where does one find such processors? No one knows if its hardware or software, but it just isn't do-able. I learned a lot about OS reading the ARM reference manual. This made me wonder why exactly this processor is so unpopular and, I think, failed. Well, PowerPC chips are not x86 compatible, but they aren't a fiasco, at least in High Performance Computing. So powerful tool developers still don't use it to its full ability to profile code. It was very hard to write code generators for; and it didn't have much reasons to succeed in the first place (It was made by Intel, so what?). My (admitted unreliable and from someone who followed that from far) recollection is that what HP(*) and Intel failed to achieve on the compiler front is the language level extraction of parallelism, not the low level which would have been present in a byte code. Maybe they were trying to make a premium tier and leave AMD, VIA, etc. DSP. This was challenging for shrink wrapped software vendors and increased the cost/risk of upgrading an Itanium platform to the current generation. by m50d on Monday February 28, 2005 @02:43PM and attached to IBM to Drop Itanium. Getting these right was hard, advanced loads especially! 0 0 1. Their non-VLIW compilers are top-notch, regularly pumping out code much faster than other compilers. BTW, I wished that AMD64 would have been some more RISCy instruction set. (*) You also seem to underestimate HP role in EPIC. The compiler simply can't find independent instructions to put in the bundles. Intel are probably the. I don't think even the Mill team make that claim (their merit factor include power). (That said, if your code makes frequent access to some localized memory areas, caching will help.). A lot of stuff can be done static that otherwise is inefficient in hardware. If multiple instructions are ready to go and they don't compete for resources, they go together in the same cycle. By making their architecture backwards compatible with the x86 instruction set, AMD was able to leverage the existing tools and developer skill sets. In general, there is simply not enough information available at the compile-time to make decisions that could possibly fill up those stalls. Why did the Intel Itanium microprocessors fail? At the time of release software developers were waiting for a decent marketshare before writing software for it and PC buyers were waiting for a decent amount of software before buying. It is possible that the investment in Itanium may have had an enriching effect on the skills of its engineers, which may have enabled them to create the next generation of successful technology. Schedule the following script to decline all Itanium updates. It probably was a bit less true in 1997. How do I place the Clock arrows inside this clock face? I'm not sure why would some one call it a failure when it is generating billions of $ for HP (although it is not just the processor; it is itanium server sales that is generating revenue). And this is where VLIW has flourished. Converting 3-gang electrical box to single. @supercat: I'm not talking about a hypothetical VM, but about a hypothetical IR that would be compiled the rest of the way by an Intel code generator. It failed to set a new standard for PC CPUs, and it failed HP as a suitable replacement for the PA-RISC and Alpha AXP, being outperformed by the end of life designs of both until the Itanium II made up the difference by sheer clock speed brute force. was not that simple; converting a large set of C programs which assumed a 32 bit integer and assumed 32 bit addressing to a native 64 bit architecture was full of pitfalls. EPIC wanted to use the area budget used by the implementation of OOO to provide more raw computing, hoping that compilers would be able to make use of it. I mean, most people. All these above factors slowed adoption of Itanium servers for the mainstream market. If it is in the processor, you have just another micro-architecture and there is no reason not to use x86 as public ISA (at least for Intel, the incompatibility has an higher cost than whatever could bring a cleaner public ISA). They will continue development and announce EPIC in 1997 at the Microprocessor Forum but the ISA won't be released until February 1999 making it impossible to create any tools for it before. - "/g/ - Technology" is 4chan's imageboard for discussing computer hardware and software, programming, and general technology. Dropping backwards compatibility would free up loads of transistor space and allow better instruction mapping decisions to be made. There a new version of Itanium out, the 2500 series. The x86-64 instruction set architecture is really not a "very good" architecture for compiler writer (but it is somehow "good enough"). Sad. Instruction-Level Parallel Processors ). Great points. What prevents a large company with deep pockets from rebranding my MIT project and killing me off? Who doesn't love being #1? I tried to install Oracle Clusterware on 2 hp-ux itanium nodes. It's commonly stated that Intel's Itanium 64-bit processor architecture failed because the revolutionary EPIC instruction set was very difficult to write a good compiler for, which meant a lack of good developer tools for IA64, which meant a lack of developers creating programs for the architecture, and so no one wanted to use hardware without much software for it, and so the platform failed, and all for the want of a horseshoe nail good compilers. Stack Overflow for Teams is a private, secure spot for you and It was slow, but it was there. PAE is the one that the market ended up using (and was extended into the 64-bit era). Performance is still much higher compared to x86. Itanium's simpler design would have pushed more stuff on the compiler (room for growth), allowing to build thinner,faster pipelines. What are the technical reasons behind the “Itanium fiasco”, if any? c) you need some significant improvements to justify an instruction set change like this. However, most general-purpose software must make plenty of random memory accesses. Intel y HP reconocen que Itanium no es competitivo y lo reemplazan por el Itanium 2 un año antes de lo planeado, en 2002. It was also an accident involving a technically inferior product that led directly to a huge monopoly for years. by jhagman on Monday February 28, 2005 @01:20PM and attached to IBM to Drop Itanium. Windows on Itanium has a WoW layer to run x86 applications. Can I (a US citizen) travel from Puerto Rico to Miami with just a copy of my passport? Do they just scrap a decade plus, multibillion project because it's visibly too late? For example, there was a looping feature where one iteration of the loop would operate on registers from different iterations. Does your organization need a developer evangelist? As a former compiler writer, it's true that being able to take an existing compiler back and tweak it for performance is better than writing one all over again. - C++. Itanium (/ aɪ ˈ t eɪ n i ə m / eye-TAY-nee-əm) is a type of Intel microprocessors with 64-bit chip architecture (not related to the by now mainstream 64-bit CPUs made by Intel and others). http://www.cs.virginia.edu/~skadron/cs654/cs654_01/slides/ting.ppt, Itanium's VLIW instruction bundles frequently increased code size by a factor of 3 to 6 compared to CISC, especially in cases when the compiler could not find parallelism. Second, Itanium world (~2001): Updates in processor design and manufacturing can deliver 1.1x speedups. IPF was in-order, for one. As a result, the Itanium failed both Intel and HP’s goals for it. It also isn’t hard to understand why Compaq’s chose Itanium. The third key difference is that implementations of out-of-order processors can be as wide as wanted, without changing the instruction set (Intel Core has 5 execution ports, other processors have 4, etc). And so it is with Itanium. As written above, not only we are still unable -- as AFAIK, even in theory -- to write compilers which have that ability, but the Itanium got enough other hard-to-implement features that it was late and its raw power was not even competitive (excepted perhaps in some niche markets with lots of FP computation) with the other high end processor when it got out of fab. AMD beat Intel at its own game by taking the same evolutionary step from the x86 family that the x86 family did from the 8086/8088 family. I guess is that they did not have enough compiler expertise in house (even if of course they did have some very good compiler experts inside, but probably not enough to make a critical mass). So this initial problem of "chicken and egg" seemed to be solved. What was an issue is the hyper-threading implementation by swapping stacks during memory IO was too slow (to empty and reload the pipeline) until Montecito etc. the 3 instructions/word have been good as long as the processor had 3 functional units to process them, but once Intel went to newer IA64 chips they added more functional units, and the instruction-level parallelism was once again hard to achieve. The architecture allowed Itanium to be relatively simple while providing tools for the compiler to eek out performance from it. What came first, the compiler, or the source? As I mentioned above, part of that dynamic information is due to non-deterministic memory latency, therefore it cannot be predicted to any degree of accuracy by compilers. If anyone does not catch the sense of fatalism from that article, let me highlight this: Load responses from a memory hierarchy which includes CPU caches and DRAM do not have a deterministic delay. Itanium failed because it used a VLIW architecture - great for specialized processing tasks on big machines but for general purpose computing (ie. Many versions of Itanium even has a small x86 CPU inside to run x86 code. Not on Itanium. 2. I don't know why they don't just take x86_64, strip out all 32bit stuff and backwards compatible things like 8087 emulation, mmx etc. Removing intersect or overlap of points in the same vector layer, Building algebraic geometry without prime ideals. Donald Knuth, a widely respected computer scientist, said in a 2008 interview that "the "Itanium" approach [was] supposed to be so terrific—until it turned out that the wished-for compilers were basically impossible to write."1. In this article Jonh Dvorak calls Itanium "one of the great fiascos of the last 50 years". Setters dependent on other instance variables in Java. Can I use deflect missile if I get an ally to shoot me? Processor architecture as a lot to do with programming. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. To make things worse, McKinley was announced back in 1998 with a 2001 shipment date and as this ZDNet article from 1999 March mentions "Word on the street suggests Merced is more likely to be a development platform with few commercial shipments -- most will wait for McKinley". It is not "... (whatever) is hard", it is that EPIC is unsuitable for any platform that has to cope with high dynamism in latency. Itanium failed to make significant inroads against IA-32 or RISC, and suffered further following the arrival of x86-64 systems which offered greater compatibility with older x86 applications. A great answer! Be the first to answer this question. Knuth was saying parallel processing is hard to take advantage of; finding and exposing fine-grained instruction-level parallelism (and explicit speculation: EPIC) at compile time for a VLIW is also a hard problem, and somewhat related to finding coarse-grained parallelism to split a sequential program or function into multiple threads to automatically take advantage of multiple cores. Other machines at the time - namely UltraSPARC - were in-order, but IPF had other considerations too. Why is a third body needed in the recombination of two hydrogen atoms? Non-mainstream RISCs are losing grounds; They didn't see that or hoped it would become mainstream; too bad it wouldn't because there weren't any reasons for that. Is there any reason why Intel didn't specify a "simple Itanium bytecode" language, and provide a tool that converts this bytecode into optimized EPIC code, leveraging their expertise as the folks who designed the system in the first place? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. It could have been some POWERPC64 (but it probably wasn't because of patent issues, because of Microsoft demands at that time, etc...). Of course, with Itanium suffering heavy delays until 2001 (2002 if you discount Merced), SGI were stuck with an architecture for which they had already cancelled future development. By 1993 they decide it's worth developing it into a product and they are looking for a semiconductor manufacturing partner and in 1994 they announce their partnership with Intel. Why do most Christians eat pork when Deuteronomy says not to? It also means yields are lower ... Not until you get into Madison and Deerfield in 2003 do you start talking about volume." like x86. Why was the first compiler written before the first interpreter? Itanium failed because it sucked. This, combined with the existing relative low density, meant that getting a decent i-cache hit rate was a) really important, and b) hard - especially since I2 only had a 16KB L1I (although it was quite fast.). Neither SPARC nor MIPS offers exceptional performance on the type of applications Alpha is good at. There is a second aspect of the failure which is also fatal. Windows Server 2008 R2 builds on the award-winning foundation of Windows Server 2008, expanding existing technology and adding new features to enable organizations to increase the reliability and flexibility of their server infrastructures. The P-system was dog slow compared with what native machine code could do. The Wikipedia article on EPIC has already outlined the many perils common to VLIW and EPIC. Historical background for EPIC instruction set architectures, EPIC: An Architecture for No existing software ran on itanium which was entirely the cause of its downfall. How is Intel killing off all the competition, using a single product line, anything but the greatest microprocessor victory of all time? I've heard some JITs gave worse perfomance than interpreters on Itanium because gcc optimized interpreter better; that's a no-go if a processor requires that level of optimizations. [failed verification] According to Intel, it skips the 45 nm process technology and uses a 32 nm process technology. Convert negadecimal to decimal (and back). Are there any Pokemon that get smaller when they evolve? Update the question so it's on-topic for Stack Overflow. Why is the pitot tube located near the nose? What would seem like a trivial effort for a company offering a software product -- recompile and retest your C code base (and at that time most would have been written in pure C!) It only takes a minute to sign up. better post this before the machune crashes! Itanium designed rested on the philosophy of very wide instruction level parallelism to scale performance of a processor when clock frequency limit is imposed due to thermal constraints. I hope my rephrasing will make the answer to that question obvious. The Intel ITANIUM. More succinctly, Intel vastly underestimated the inertia from those wearing the yoke of backward compatibility. The first Itanium chip was delayed to 2001 and failed to impress most potential customers who stuck to their x86, Power and SPARC chips. What a truly pathetic business model! Compilers have access to optimization info that OOO hardware won't have at run time, but OOO hardware has access to information that is not available to the compiler, It is not that "compiler ... extracting parallelism is hard". Software Engineering Stack Exchange is a question and answer site for professionals, academics, and students working within the systems development life cycle. MIPS, Alpha, PA-RISC -- gone. Thanks. As he mentions near the end, at the mere sight of Itanium, "one promising project after another was dropped". such as unanticipated memory latency costs. What is this “denormal data” about ? Same again when they moved to Core Duo. Those instructions are executed speculatively anyway (based on branch prediction, primarily). AMD was something of a threat but Intel was the king of the hill. It then e-mails an HTML report with the following column headings: Title, KB Article, Classification, Product Title, Product Family The problem was it wasn't one feature, it was many. In reality, prefetching is only profitable if you are performing streaming operations (reading memory in a sequential, or highly predictable manner). 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When you could really properly fill it, which often involved either PGO or hand-coding, it did great - but a lot of the time, performance from compilers was really just uninspiring. Why did the Intel Itanium microprocessors fail? Modern x86 processors, with the exception of Intel Atom (pre Silvermont) and I believe AMD E-3**/4**, are all out-of-order processors. The compilers had to patch up late-to-detect flaws of CPU implementations, and some of the performance edge was lost to hard to predict mistakes. Why do new language versions typically use an early compiler version for the bootstrap compiler? (This was before Thumb2, et al - RISC still meant fixed-length rigidity.) The second key difference is that out-of-order processors determine these schedules dynamically (i.e., each dynamic instruction is scheduled independently; the VLIW compiler operates on static instructions). With the Alpha chip design team at AMD, the Athlon already showed their ability to create competitive performance and x86-64 takes away the 64 bit advantage. In a CPU like the Itanium or the SPARC with 200+ registers, this can be rather slow. At same generation and fab technology, it would have been running faster and capped all the same but a bit higher, with maybe other doors to open to push Moore's law. IPF didn't make it easy to generate great code, and it was unforgiving when code wasn't great. @rwong, I made a TLDR of what I consider my main points. Of course, technical reasons aren’t the only reason why Itanium failed. It's its place in time and market forces. Aleksandr, there are multiple parts to the answer. I think Itanium still has its market - high end systems and HP blade servers. Itanium instructions were, by nature, not especially dense - a 128-bit bundle contained three operations and a 5-bit template field, which described the operations in the bundle, and whether they could all issue together. David W. Hess (dwhess@banishedsouls.org) on 7/6/09 wrote: >My observations at the time were that the 386 performance increase over the 286 That pretty much nails the problem. Part of it were technical reasons, such as that the initial product was too large/expensive and not fast enough to be competitive, especially not compared to AMD's x64. AMD's move was so successful that Intel (and Via) were essentially forced to adopt the x86-64 architecture. The AMD Opteron. What do do at this juncture? What are multiplexed and non-multiplexed address pins? Working with WSUS, I sometimes find myself declining the exact same type of updates each month after Patch Tuesday. “The operation was a success, although the patient died,” goes the old surgeon’s joke. Catastrophe hits in 1999 October when AMD announces the x86-64. Demonstrating how slowly markets move, it has taken years for applications to catch up to 64-bit, multi-threaded programming, and even now 4GB RAM is standard on low-end PCs. It seems to me that if the explicit parallelism in EPIC was difficult for compiler vendors to implement... why put that burden on them in the first place? AFAIK, Intel EPIC failed because compilation for EPIC is really hard, and also because when compiler technology slowly and gradually improved, other competitors where also able to improve their compiler (e.g. rev 2020.12.2.38097, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide. To help explain why it is not always possible to find enough work to fill up the stalls, here is how one could visualize it. The compilers became quite good at it, especially when using PGO profiling (I worked at HP and HP's compiler tended to outperform Intel's). So you have to know how and why it works at least a little. With Itanium due in 1999 (and full of hype at this point), SGI canned the "Beast" project and decided to migrate. Moderators: NeilBlanchard , Ralf Hutter , sthayashi , Lawrence Lee Is it worth getting a mortgage with early repayment or an offset mortgage? site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. As Robert Munn pointed out -- it was the lack of backward compatibility that killed the Itanium ( and many other "new" technologies). It is an example of failure to apply the 80-20 rule of optimization: Optimizing things that are already fast will not meaningfully improve overall performance, unless the slower things are also being optimized. Why?? Why was the Itanium processor difficult to write a compiler for? In response to answer by Basile Starynkevitch. 11 years later he's still basically right: per-thread performance is still very important for most non-server software, and something that CPU vendors focus on because many cores is no substitute. your coworkers to find and share information. There were a number of reasons why Itanium (as it became known in 1999) failed to live up to its promise. And as several explained, EPIC compilation is really hard. Why Itanium Failed To Be Adopted Widely. Do MEMS accelerometers have a lower frequency limit? by SunFan on Monday February 28, 2005 @01:50PM and attached to IBM to Drop Itanium. Many compiler writers don't see it this way - they always liked the fact that Itanium gives them more to do, puts them back in control, etc. Where did the concept of a (fantasy-style) "dungeon" originate? PSE avoids this layer by instead using 4 reserved bits in the page tables to specify the high bits. Regardless of the qualitative differences between the architectures, IA64 could not overcome the momentum of its own x86 platform once AMD added the x86-64 extensions. PowerPC is only surviving in the embedded space. The issue with EPIC is that it can use only the parallelism that a compiler can find, and extracting that parallelism is hard. IPF was meant to be backwards compatible, but once AMD64 launched it became moot, the battle was lost and I believe the X86 hardware in the CPU was just stripped to retarget as a server CPU. What is the easiest way to embed a bluetooth to any device? As I recall at the time, the issue was not just the particulars of IA64, it was the competition with AMD's x86-64 instruction set. Recent SPARCs devote a fair amount of chip area to optimizing this, ... 32bit opcodes but not more! In other words, it is not always possible (within the confines of software logic) to calculate the address up front, or to find enough work to do to fill up the stalls between these three steps. most software companies would have bitten the bullet and made the effort. What killed Itanium was shipment delays that opened the door for AMD64 to step in before software vendors commited to migrate to IA64 for 64 bit apps. So fast chip with a reasonable OS but a very limited set of software available, therefore not many people bought it, therefore not many software companies provided products for it. The main problem is that non-deterministic memory latency means that whatever "instruction pairing" one has encoded for the VLIW/EPIC processor will end up being stalled by memory access. The compiler aspect was not the only aspect which was overly ambitious. Why Itanium’s imminent demise increases the risks with OpenVMS applications by Paul Holland , VP of Operations, Advanced The OpenVMS operating system was developed back in the 1970s, and it continues to drive numerous mission-critical business systems worldwide. Working with WSUS, I sometimes find myself declining the exact same type of updates each month after Patch Tuesday. Solamente algunos miles de los Itanium se vendieron, debido a la disponibilidad limitada causada por baja producción, relativamente pobre rendimiento y alto coste. The Itanium chip might have given Intel much grief, but it is through difficult and sometimes failed projects that companies learn. Optimizing instructions that do not stall (register-only, arithmetic) will not help with the performance issues caused by instructions that are very likely to stall (memory access). Why did the Intel Itanium microprocessors fail? site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. Early chips were atrocious. Windows Server 2008 R2 with Service Pack 1 (SP1) includes previously released updates for Windows Server 2008 R2. @Nubok: Not correct - there were two mechanisms, PAE & PSE-36, to gain access to memory >4GB on 32-bit machines and none involved segment descriptors at all. So how is this different from VLIW? Had AMD never come up with x86-64, I'm sure Intel would have been happy to have everyone who wanted to jump to 4GB+ RAM pay a hefty premium for years for that privilege. And downvoted. It's not like a good, well-understood solution to this problem didn't already exist: put that burden on Intel instead and give the compiler-writers a simpler target. Compilers have decent success at extracting instruction-level parallelism, as are modern CPU hardware. Complexity of compilers? VLIW machines can and do execute multiple bundles at once (if they don't conflict). They started a visionary research project using personnel and IP from two notable VLIW companies in the 80s (Cydrome and Multiflow -- the Multiflow Trace is btw the negative answer posed in the title, it was a successful VLIW compiler), this was the Precision Architecture Wide-Word. You are probably too young to know the entire story. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. Was Itanium a deliberate attempt to make a premium platform and pull the rug out from under AMD, VIA, etc.? The big problem is that when it asked me to run root.sh on both node 1 & 2 it returns Checking to see if Oracle CRS stack is already configured Setting the permissions on OCR backup directory Setting up NS directories Failed to upgrade Oracle Cluster Registry configuration. Leaving optimization to the compiler was a good idea. I guess that their management underestimated the efforts needed to make a compiler. For example, if a processor has all of the following: Where does one find such processors? No one knows if its hardware or software, but it just isn't do-able. I learned a lot about OS reading the ARM reference manual. This made me wonder why exactly this processor is so unpopular and, I think, failed. Well, PowerPC chips are not x86 compatible, but they aren't a fiasco, at least in High Performance Computing. So powerful tool developers still don't use it to its full ability to profile code. It was very hard to write code generators for; and it didn't have much reasons to succeed in the first place (It was made by Intel, so what?). My (admitted unreliable and from someone who followed that from far) recollection is that what HP(*) and Intel failed to achieve on the compiler front is the language level extraction of parallelism, not the low level which would have been present in a byte code. Maybe they were trying to make a premium tier and leave AMD, VIA, etc. DSP. This was challenging for shrink wrapped software vendors and increased the cost/risk of upgrading an Itanium platform to the current generation. by m50d on Monday February 28, 2005 @02:43PM and attached to IBM to Drop Itanium. Getting these right was hard, advanced loads especially! 0 0 1. Their non-VLIW compilers are top-notch, regularly pumping out code much faster than other compilers. BTW, I wished that AMD64 would have been some more RISCy instruction set. (*) You also seem to underestimate HP role in EPIC. The compiler simply can't find independent instructions to put in the bundles. Intel are probably the. I don't think even the Mill team make that claim (their merit factor include power). (That said, if your code makes frequent access to some localized memory areas, caching will help.). A lot of stuff can be done static that otherwise is inefficient in hardware. If multiple instructions are ready to go and they don't compete for resources, they go together in the same cycle. By making their architecture backwards compatible with the x86 instruction set, AMD was able to leverage the existing tools and developer skill sets. In general, there is simply not enough information available at the compile-time to make decisions that could possibly fill up those stalls. Why did the Intel Itanium microprocessors fail? At the time of release software developers were waiting for a decent marketshare before writing software for it and PC buyers were waiting for a decent amount of software before buying. It is possible that the investment in Itanium may have had an enriching effect on the skills of its engineers, which may have enabled them to create the next generation of successful technology. Schedule the following script to decline all Itanium updates. It probably was a bit less true in 1997. How do I place the Clock arrows inside this clock face? I'm not sure why would some one call it a failure when it is generating billions of $ for HP (although it is not just the processor; it is itanium server sales that is generating revenue). And this is where VLIW has flourished. Converting 3-gang electrical box to single. @supercat: I'm not talking about a hypothetical VM, but about a hypothetical IR that would be compiled the rest of the way by an Intel code generator. It failed to set a new standard for PC CPUs, and it failed HP as a suitable replacement for the PA-RISC and Alpha AXP, being outperformed by the end of life designs of both until the Itanium II made up the difference by sheer clock speed brute force. was not that simple; converting a large set of C programs which assumed a 32 bit integer and assumed 32 bit addressing to a native 64 bit architecture was full of pitfalls. EPIC wanted to use the area budget used by the implementation of OOO to provide more raw computing, hoping that compilers would be able to make use of it. I mean, most people. All these above factors slowed adoption of Itanium servers for the mainstream market. If it is in the processor, you have just another micro-architecture and there is no reason not to use x86 as public ISA (at least for Intel, the incompatibility has an higher cost than whatever could bring a cleaner public ISA). They will continue development and announce EPIC in 1997 at the Microprocessor Forum but the ISA won't be released until February 1999 making it impossible to create any tools for it before. - "/g/ - Technology" is 4chan's imageboard for discussing computer hardware and software, programming, and general technology. Dropping backwards compatibility would free up loads of transistor space and allow better instruction mapping decisions to be made. There a new version of Itanium out, the 2500 series. The x86-64 instruction set architecture is really not a "very good" architecture for compiler writer (but it is somehow "good enough"). Sad. Instruction-Level Parallel Processors ). Great points. What prevents a large company with deep pockets from rebranding my MIT project and killing me off? Who doesn't love being #1? I tried to install Oracle Clusterware on 2 hp-ux itanium nodes. It's commonly stated that Intel's Itanium 64-bit processor architecture failed because the revolutionary EPIC instruction set was very difficult to write a good compiler for, which meant a lack of good developer tools for IA64, which meant a lack of developers creating programs for the architecture, and so no one wanted to use hardware without much software for it, and so the platform failed, and all for the want of a horseshoe nail good compilers. Stack Overflow for Teams is a private, secure spot for you and It was slow, but it was there. PAE is the one that the market ended up using (and was extended into the 64-bit era). Performance is still much higher compared to x86. Itanium's simpler design would have pushed more stuff on the compiler (room for growth), allowing to build thinner,faster pipelines. What are the technical reasons behind the “Itanium fiasco”, if any? c) you need some significant improvements to justify an instruction set change like this. However, most general-purpose software must make plenty of random memory accesses. Intel y HP reconocen que Itanium no es competitivo y lo reemplazan por el Itanium 2 un año antes de lo planeado, en 2002. It was also an accident involving a technically inferior product that led directly to a huge monopoly for years. by jhagman on Monday February 28, 2005 @01:20PM and attached to IBM to Drop Itanium. Windows on Itanium has a WoW layer to run x86 applications. Can I (a US citizen) travel from Puerto Rico to Miami with just a copy of my passport? Do they just scrap a decade plus, multibillion project because it's visibly too late? For example, there was a looping feature where one iteration of the loop would operate on registers from different iterations. Does your organization need a developer evangelist? As a former compiler writer, it's true that being able to take an existing compiler back and tweak it for performance is better than writing one all over again. - C++. Itanium (/ aɪ ˈ t eɪ n i ə m / eye-TAY-nee-əm) is a type of Intel microprocessors with 64-bit chip architecture (not related to the by now mainstream 64-bit CPUs made by Intel and others). http://www.cs.virginia.edu/~skadron/cs654/cs654_01/slides/ting.ppt, Itanium's VLIW instruction bundles frequently increased code size by a factor of 3 to 6 compared to CISC, especially in cases when the compiler could not find parallelism. Second, Itanium world (~2001): Updates in processor design and manufacturing can deliver 1.1x speedups. IPF was in-order, for one. As a result, the Itanium failed both Intel and HP’s goals for it. It also isn’t hard to understand why Compaq’s chose Itanium. The third key difference is that implementations of out-of-order processors can be as wide as wanted, without changing the instruction set (Intel Core has 5 execution ports, other processors have 4, etc). And so it is with Itanium. As written above, not only we are still unable -- as AFAIK, even in theory -- to write compilers which have that ability, but the Itanium got enough other hard-to-implement features that it was late and its raw power was not even competitive (excepted perhaps in some niche markets with lots of FP computation) with the other high end processor when it got out of fab. AMD beat Intel at its own game by taking the same evolutionary step from the x86 family that the x86 family did from the 8086/8088 family. I guess is that they did not have enough compiler expertise in house (even if of course they did have some very good compiler experts inside, but probably not enough to make a critical mass). So this initial problem of "chicken and egg" seemed to be solved. What was an issue is the hyper-threading implementation by swapping stacks during memory IO was too slow (to empty and reload the pipeline) until Montecito etc. the 3 instructions/word have been good as long as the processor had 3 functional units to process them, but once Intel went to newer IA64 chips they added more functional units, and the instruction-level parallelism was once again hard to achieve. The architecture allowed Itanium to be relatively simple while providing tools for the compiler to eek out performance from it. What came first, the compiler, or the source? As I mentioned above, part of that dynamic information is due to non-deterministic memory latency, therefore it cannot be predicted to any degree of accuracy by compilers. If anyone does not catch the sense of fatalism from that article, let me highlight this: Load responses from a memory hierarchy which includes CPU caches and DRAM do not have a deterministic delay. Itanium failed because it used a VLIW architecture - great for specialized processing tasks on big machines but for general purpose computing (ie. Many versions of Itanium even has a small x86 CPU inside to run x86 code. Not on Itanium. 2. I don't know why they don't just take x86_64, strip out all 32bit stuff and backwards compatible things like 8087 emulation, mmx etc. Removing intersect or overlap of points in the same vector layer, Building algebraic geometry without prime ideals. Donald Knuth, a widely respected computer scientist, said in a 2008 interview that "the "Itanium" approach [was] supposed to be so terrific—until it turned out that the wished-for compilers were basically impossible to write."1. In this article Jonh Dvorak calls Itanium "one of the great fiascos of the last 50 years". Setters dependent on other instance variables in Java. Can I use deflect missile if I get an ally to shoot me? Processor architecture as a lot to do with programming. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. To make things worse, McKinley was announced back in 1998 with a 2001 shipment date and as this ZDNet article from 1999 March mentions "Word on the street suggests Merced is more likely to be a development platform with few commercial shipments -- most will wait for McKinley". It is not "... (whatever) is hard", it is that EPIC is unsuitable for any platform that has to cope with high dynamism in latency. Itanium failed to make significant inroads against IA-32 or RISC, and suffered further following the arrival of x86-64 systems which offered greater compatibility with older x86 applications. A great answer! Be the first to answer this question. Knuth was saying parallel processing is hard to take advantage of; finding and exposing fine-grained instruction-level parallelism (and explicit speculation: EPIC) at compile time for a VLIW is also a hard problem, and somewhat related to finding coarse-grained parallelism to split a sequential program or function into multiple threads to automatically take advantage of multiple cores. Other machines at the time - namely UltraSPARC - were in-order, but IPF had other considerations too. Why is a third body needed in the recombination of two hydrogen atoms? Non-mainstream RISCs are losing grounds; They didn't see that or hoped it would become mainstream; too bad it wouldn't because there weren't any reasons for that. Is there any reason why Intel didn't specify a "simple Itanium bytecode" language, and provide a tool that converts this bytecode into optimized EPIC code, leveraging their expertise as the folks who designed the system in the first place? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. It could have been some POWERPC64 (but it probably wasn't because of patent issues, because of Microsoft demands at that time, etc...). Of course, with Itanium suffering heavy delays until 2001 (2002 if you discount Merced), SGI were stuck with an architecture for which they had already cancelled future development. By 1993 they decide it's worth developing it into a product and they are looking for a semiconductor manufacturing partner and in 1994 they announce their partnership with Intel. Why do most Christians eat pork when Deuteronomy says not to? It also means yields are lower ... Not until you get into Madison and Deerfield in 2003 do you start talking about volume." like x86. Why was the first compiler written before the first interpreter? Itanium failed because it sucked. This, combined with the existing relative low density, meant that getting a decent i-cache hit rate was a) really important, and b) hard - especially since I2 only had a 16KB L1I (although it was quite fast.). Neither SPARC nor MIPS offers exceptional performance on the type of applications Alpha is good at. There is a second aspect of the failure which is also fatal. Windows Server 2008 R2 builds on the award-winning foundation of Windows Server 2008, expanding existing technology and adding new features to enable organizations to increase the reliability and flexibility of their server infrastructures. The P-system was dog slow compared with what native machine code could do. The Wikipedia article on EPIC has already outlined the many perils common to VLIW and EPIC. Historical background for EPIC instruction set architectures, EPIC: An Architecture for No existing software ran on itanium which was entirely the cause of its downfall. How is Intel killing off all the competition, using a single product line, anything but the greatest microprocessor victory of all time? I've heard some JITs gave worse perfomance than interpreters on Itanium because gcc optimized interpreter better; that's a no-go if a processor requires that level of optimizations. [failed verification] According to Intel, it skips the 45 nm process technology and uses a 32 nm process technology. Convert negadecimal to decimal (and back). Are there any Pokemon that get smaller when they evolve? Update the question so it's on-topic for Stack Overflow. Why is the pitot tube located near the nose? What would seem like a trivial effort for a company offering a software product -- recompile and retest your C code base (and at that time most would have been written in pure C!) It only takes a minute to sign up. better post this before the machune crashes! Itanium designed rested on the philosophy of very wide instruction level parallelism to scale performance of a processor when clock frequency limit is imposed due to thermal constraints. I hope my rephrasing will make the answer to that question obvious. The Intel ITANIUM. More succinctly, Intel vastly underestimated the inertia from those wearing the yoke of backward compatibility. The first Itanium chip was delayed to 2001 and failed to impress most potential customers who stuck to their x86, Power and SPARC chips. What a truly pathetic business model! Compilers have access to optimization info that OOO hardware won't have at run time, but OOO hardware has access to information that is not available to the compiler, It is not that "compiler ... extracting parallelism is hard". Software Engineering Stack Exchange is a question and answer site for professionals, academics, and students working within the systems development life cycle. MIPS, Alpha, PA-RISC -- gone. Thanks. As he mentions near the end, at the mere sight of Itanium, "one promising project after another was dropped". such as unanticipated memory latency costs. What is this “denormal data” about ? Same again when they moved to Core Duo. Those instructions are executed speculatively anyway (based on branch prediction, primarily). AMD was something of a threat but Intel was the king of the hill. It then e-mails an HTML report with the following column headings: Title, KB Article, Classification, Product Title, Product Family The problem was it wasn't one feature, it was many. In reality, prefetching is only profitable if you are performing streaming operations (reading memory in a sequential, or highly predictable manner). 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- "/g/ - Technology" is 4chan's imageboard for discussing computer hardware and software, programming, and general technology. There a new version of Itanium out, the 2500 series. It's valid. You need a C++ compiler, Java and given that the main user base would be Windows some sort of Visual Basic. Several issues: a) add something to the instruction set, and you need to support it even if it makes no sense anymore (e.g., delayed branch slots). For scientific computation, where you get at least a few dozens of instructions per basic block, VLIW probably works fine. Also the IA64 architecture has builtin some strong limitations, e.g. Can I (a US citizen) travel from Puerto Rico to Miami with just a copy of my passport? Itanium came out in 1997. Well, they were also late (planned for 98, first shipment in 2001) and when they finally delivered the hardware, I'm not even sure that it delivered what was promised for the earlier date (IIRC, they at least dropped part of the x86 emulation which was initially planned), so I'm not sure that even if the compilation problems has been solved (and AFAIK, it has not yet), they would have succeeded. In hindsight, the failure of Itanium (and the continued pouring of R&D effort into a failure, despite obvious evidence) is an example of organizational failure, and deserves to be studied in depth. Is there any deterministic identifying information? Get a clue if you got the bucks to run an itanium, why criple it with the sins of the past. Later, further fuelling the Osborne effect, in the beginning of 2002 after Itanium sales off to a slow start one could read analysts saying "One problem is that McKinley...is expensive to manufacture. Itanium failed because VLIW for today's workloads is simply an awful idea. They employ many talented engineers and computer scientists. Is it more efficient to send a fleet of generation ships or one massive one? This meant you couldn't rely on reorder to save you in the event of a cache miss or other long-running event. TL;DR: 1/ there are other aspects in the failure of Itanium than the compiler issues and they may very well be enough to explain it; 2/ a byte code would not have solved the compiler issues. They were the market power at the time. Sort of the best out of both approaches. How do I know if the compiler broke my code and what do I do if it was the compiler? It was a commercial failure. How do people recognise the frequency of a played note? Even worse, you didn't always have enough ILP to fit the template you were using - so you'd have to NOP-pad to fill out the template or the bundle. Erm. While he describes the over-optimistic market expectations and the dramatic financial outcome of the idea, he doesn't go into the technical details of this epic fail. The engineering part was actually pretty successful. -- so where people were strung along from 1998 to 2002 to wait for McKinley now that the year of McKinley arrived, they were told, wait that's too expensive, the next one will be better, or if not, then the one after. It is I guess technically possible to enhance out-of-order execution this way, though I'm not aware of solid approaches. More details on this issue are available here. Itanium never achieved the necessary price/performance advantage necessary to overcome "platform inertia" because it was frequently delayed to compensate for issues 1-4. This made for an effective 42.6 bit operation size - compare to 32 bits for most of the commercial RISCs' operations at the time. Back then (and maybe now... not sure) writing a compiler back-end was something a team of 4 or 5 devs could do in a year. In my opinion it is very "programming-related", because whatever we program gets executed by that processor-thingie inside the machines. Itanium’s demise approaches: Intel to stop shipments in mid-2021 Intel's grand adventure with smart compilers and dumb processors comes to an end. POWER would be an option, but IBM is a competitor and Compaq already has a working relationship with Intel. It merely says that the burden of indicating data dependency now falls on the compiler. Under-performance? But they won't admit how miserably it failed. For example, early Itanium CPUs execute up to 2 VLIW bundles per clock cycle, 6 instructions, with later designs (2011's Poulson and later) running up to 4 bundles = 12 instructions per clock, with SMT to take those instructions from multiple threads. We're stuck at 3+GHz, and dumping cores with not enough use for it. There was a decent operating system (NT) and a good C compiler available. Any memory access (read or write) has to be scheduled by DMA transfer; Every instruction has the same execution latency. Is the microsoft C compiler (cl.exe) a compiler driver or a compiler? Hybrids between von-Neumann and dataflow do exist (Wavescalar). PowerPC worked because Apple worked very hard to provide an emulation layer to 68000. Performance-wise with similar specs (caches, cores, etc) they just beat the crap out of Itanium. Itanium - Why it failed? Podcast 291: Why developers are demanding more ethics in tech, “Question closed” notifications experiment results and graduation, MAINTENANCE WARNING: Possible downtime early morning Dec 2, 4, and 9 UTC…. The first key difference between VLIW and out-of-order is that the the out-of-order processor can choose instructions from different basic blocks to execute at the same time. Asked by Adah Doyle. Burdening a new supposedly-faster architecture with a slow VM would probably not make buyers very happy. Maybe they thought that IA64 would be so much better than anything else that they could move the entire market. In my opinion, failure to cope with memory latency is the sole cause of death of EPIC architecture. Granted, the vendor's other ventures, such as hyperthreading, SIMD, etc., appears to be highly successful. Why did George Lucas ban David Prowse (actor of Darth Vader) from appearing at sci-fi conventions? Let me put it another way. The question waited for you so long :-) As for the quote, I believe it is from Donald Knuth: Why has noone made an architecture where instructions carry additional info (about dependencies, etc) to make out-of-order easier/cheaper? Simple. The real reason for this epic failure was the phenomenon called "too much invested to quit" (also see the Dollar Auction) with a side of Osborne effect. Is this purely down to marketing? Intel Corp. is working with Itanium 2 server vendors on a bug that has surfaced in the McKinley version of its Itanium processor family, an Intel spokeswoman said today. Aleksandr, as an aside, dataflow architectures have all dependencies explicit. Look at SGI Mips, DEC Alpha... Itanium was just supported by the loosers, SGI & HP servers, companies with managements that piled on strategic business mistakes. Reordering of memory and arithmetic instructions by modern compilers is the evidence that it has no problem identifying operations that are independently and thus concurrently executable. What is the easiest way in C# to check if hard disk is SSD without writing any file on hard disk? Perhaps RISC-V (which is an open source ISA) will gradually succeed enough to make it competitive to other processors. There is a hint in "Intel would have been happy to have everyone [...]" but it's not clear to me if you're implying whether this was a deliberate decision by Intel (and if so, what you have to support this assertion). How can one plan structures and fortifications in advance to help regaining control over their city walls? But why was the compiler stuff such a difficult technical problem? Our "pub" where you can post about things completely Off Topic or about non-silent PC issues. Why Itanium Failed To Be Adopted Widely. The coping strategies (mentioned in the same article) assumes that software-based prefetching can be used to recover at least part of the performance loss due to non-deterministic latency from memory access. I read that article, and I'm completely missing the "fiasco" he refers to. Had IA64 become a dominant chip (or even a popular one!) Note that the coping strategy employed by EPIC (mentioned in the Wikipedia article linked above) does not actually solve the issue. The problem is that the CPU is still going to idle for tens to hundreds of cycles over a memory access. But why was the compiler stuff such a difficult technical problem? There were specific reasons why Intel did what they did, unfortunately I cannot dig up any definitive resources to provide an answer. Building algebraic geometry without prime ideals, I accidentally added a character, and then forgot to write them in for the rest of the series. Incompatibility with x86 code? We chose at the time instead to build PowerPC back ends to support the flavors of Unix boxes that were being built on it. However the first gens focussed transistor count on other performance schemes since the compiler handled a lot of the hard stuff. Re:Why Itanium Failed. 开一个生日会 explanation as to why 开 is used here? It increases the size of page table entries to 8 bytes, allowing bigger addresses. Asked by Adah Doyle. As to why Itanium failed I am not informed enough to give you a complete answer. what 99.9% of people do) it wasn't much faster than x86.Are computers really 'too slow' now? What IBM said was that with PowerPC, you could compile bytecode quickly and the CPU would make it fast. For more modern workloads, where oftentimes you get about 6-7 instructions per basic block, it simply doesn't (that's the average, IIRC, for SPEC2000). In short, Intel tried to make a revolutionary leap with the IA64 architecture, and AMD made an evolutionary step with x86-64. I updated my answer in response to one of your claim. (*) By "cope with", it is necessary to achieve reasonably good execution performance (in other words, "cost-competitive"), which necessitates not letting the CPU fall idle for tens to hundreds of cycles ever so often. Itanium sucked performance wise for the money invested in it. But still, the market share for Itaniums in HPC was growing for some period. It is still not at all evident that x86 will win over everything, for example the DEC Alpha AXP looked way more like the future of high end. x86-64 smashed that barrier and opened up higher power computing to everyone. So this was not really a problem. Itanium - Why it failed? Why was the caret used for XOR instead of exponentiation? I was told that there are lots of partial reasons that all accumulated into a non-viable product in the market. As you look to deploy these feature updates in your organization, I want to tell you about some changes we are making to the way Windows Server Update Services … It's not like a good, well-understood solution to this problem didn't already exist: put that burden on Intel instead and give the compiler-writers a simpler target. There were a number of reasons why Itanium (as it became known in 1999) failed to live up to its promise. I don't buy the explanation that IA64 was too difficult to program for. Who first called natural satellites "moons"? AMD had a better approach to 64-bit and Intel hadn't yet awoken to the concept that Linux could actually be good for them. However, as a result, the page size is limited to 2M for pages that map >4GB . What you describes is a bit what Transmeta tried to do with their code morphing software (which was dynamically translating x86 "bytecode" into Transmeta internal machine code). CPU hardware has the advantage of dynamic scheduling, and I don't think there is an example of statically scheduled processor which is competitive on pure performance for single thread with OOO. Does your organization need a developer evangelist? The question can be rephrased as: "Given a hardware platform that is destined to be a failure, why (1) didn't (2) couldn't the compiler writers make a heroic effort to redeem it?". When you could really properly fill it, which often involved either PGO or hand-coding, it did great - but a lot of the time, performance from compilers was really just uninspiring. Why did the Intel Itanium microprocessors fail? Modern x86 processors, with the exception of Intel Atom (pre Silvermont) and I believe AMD E-3**/4**, are all out-of-order processors. The compilers had to patch up late-to-detect flaws of CPU implementations, and some of the performance edge was lost to hard to predict mistakes. Why do new language versions typically use an early compiler version for the bootstrap compiler? (This was before Thumb2, et al - RISC still meant fixed-length rigidity.) The second key difference is that out-of-order processors determine these schedules dynamically (i.e., each dynamic instruction is scheduled independently; the VLIW compiler operates on static instructions). With the Alpha chip design team at AMD, the Athlon already showed their ability to create competitive performance and x86-64 takes away the 64 bit advantage. In a CPU like the Itanium or the SPARC with 200+ registers, this can be rather slow. At same generation and fab technology, it would have been running faster and capped all the same but a bit higher, with maybe other doors to open to push Moore's law. IPF didn't make it easy to generate great code, and it was unforgiving when code wasn't great. @rwong, I made a TLDR of what I consider my main points. Of course, technical reasons aren’t the only reason why Itanium failed. It's its place in time and market forces. Aleksandr, there are multiple parts to the answer. I think Itanium still has its market - high end systems and HP blade servers. Itanium instructions were, by nature, not especially dense - a 128-bit bundle contained three operations and a 5-bit template field, which described the operations in the bundle, and whether they could all issue together. David W. Hess (dwhess@banishedsouls.org) on 7/6/09 wrote: >My observations at the time were that the 386 performance increase over the 286 That pretty much nails the problem. Part of it were technical reasons, such as that the initial product was too large/expensive and not fast enough to be competitive, especially not compared to AMD's x64. AMD's move was so successful that Intel (and Via) were essentially forced to adopt the x86-64 architecture. The AMD Opteron. What do do at this juncture? What are multiplexed and non-multiplexed address pins? Working with WSUS, I sometimes find myself declining the exact same type of updates each month after Patch Tuesday. “The operation was a success, although the patient died,” goes the old surgeon’s joke. Catastrophe hits in 1999 October when AMD announces the x86-64. Demonstrating how slowly markets move, it has taken years for applications to catch up to 64-bit, multi-threaded programming, and even now 4GB RAM is standard on low-end PCs. It seems to me that if the explicit parallelism in EPIC was difficult for compiler vendors to implement... why put that burden on them in the first place? AFAIK, Intel EPIC failed because compilation for EPIC is really hard, and also because when compiler technology slowly and gradually improved, other competitors where also able to improve their compiler (e.g. rev 2020.12.2.38097, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide. To help explain why it is not always possible to find enough work to fill up the stalls, here is how one could visualize it. The compilers became quite good at it, especially when using PGO profiling (I worked at HP and HP's compiler tended to outperform Intel's). So you have to know how and why it works at least a little. With Itanium due in 1999 (and full of hype at this point), SGI canned the "Beast" project and decided to migrate. Moderators: NeilBlanchard , Ralf Hutter , sthayashi , Lawrence Lee Is it worth getting a mortgage with early repayment or an offset mortgage? site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. As Robert Munn pointed out -- it was the lack of backward compatibility that killed the Itanium ( and many other "new" technologies). It is an example of failure to apply the 80-20 rule of optimization: Optimizing things that are already fast will not meaningfully improve overall performance, unless the slower things are also being optimized. Why?? Why was the Itanium processor difficult to write a compiler for? In response to answer by Basile Starynkevitch. 11 years later he's still basically right: per-thread performance is still very important for most non-server software, and something that CPU vendors focus on because many cores is no substitute. your coworkers to find and share information. There were a number of reasons why Itanium (as it became known in 1999) failed to live up to its promise. And as several explained, EPIC compilation is really hard. Why Itanium Failed To Be Adopted Widely. Do MEMS accelerometers have a lower frequency limit? by SunFan on Monday February 28, 2005 @01:50PM and attached to IBM to Drop Itanium. Many compiler writers don't see it this way - they always liked the fact that Itanium gives them more to do, puts them back in control, etc. Where did the concept of a (fantasy-style) "dungeon" originate? PSE avoids this layer by instead using 4 reserved bits in the page tables to specify the high bits. Regardless of the qualitative differences between the architectures, IA64 could not overcome the momentum of its own x86 platform once AMD added the x86-64 extensions. PowerPC is only surviving in the embedded space. The issue with EPIC is that it can use only the parallelism that a compiler can find, and extracting that parallelism is hard. IPF was meant to be backwards compatible, but once AMD64 launched it became moot, the battle was lost and I believe the X86 hardware in the CPU was just stripped to retarget as a server CPU. What is the easiest way to embed a bluetooth to any device? As I recall at the time, the issue was not just the particulars of IA64, it was the competition with AMD's x86-64 instruction set. Recent SPARCs devote a fair amount of chip area to optimizing this, ... 32bit opcodes but not more! In other words, it is not always possible (within the confines of software logic) to calculate the address up front, or to find enough work to do to fill up the stalls between these three steps. most software companies would have bitten the bullet and made the effort. What killed Itanium was shipment delays that opened the door for AMD64 to step in before software vendors commited to migrate to IA64 for 64 bit apps. So fast chip with a reasonable OS but a very limited set of software available, therefore not many people bought it, therefore not many software companies provided products for it. The main problem is that non-deterministic memory latency means that whatever "instruction pairing" one has encoded for the VLIW/EPIC processor will end up being stalled by memory access. The compiler aspect was not the only aspect which was overly ambitious. Why Itanium’s imminent demise increases the risks with OpenVMS applications by Paul Holland , VP of Operations, Advanced The OpenVMS operating system was developed back in the 1970s, and it continues to drive numerous mission-critical business systems worldwide. Working with WSUS, I sometimes find myself declining the exact same type of updates each month after Patch Tuesday. Solamente algunos miles de los Itanium se vendieron, debido a la disponibilidad limitada causada por baja producción, relativamente pobre rendimiento y alto coste. The Itanium chip might have given Intel much grief, but it is through difficult and sometimes failed projects that companies learn. Optimizing instructions that do not stall (register-only, arithmetic) will not help with the performance issues caused by instructions that are very likely to stall (memory access). Why did the Intel Itanium microprocessors fail? site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. Early chips were atrocious. Windows Server 2008 R2 with Service Pack 1 (SP1) includes previously released updates for Windows Server 2008 R2. @Nubok: Not correct - there were two mechanisms, PAE & PSE-36, to gain access to memory >4GB on 32-bit machines and none involved segment descriptors at all. So how is this different from VLIW? Had AMD never come up with x86-64, I'm sure Intel would have been happy to have everyone who wanted to jump to 4GB+ RAM pay a hefty premium for years for that privilege. And downvoted. It's not like a good, well-understood solution to this problem didn't already exist: put that burden on Intel instead and give the compiler-writers a simpler target. Compilers have decent success at extracting instruction-level parallelism, as are modern CPU hardware. Complexity of compilers? VLIW machines can and do execute multiple bundles at once (if they don't conflict). They started a visionary research project using personnel and IP from two notable VLIW companies in the 80s (Cydrome and Multiflow -- the Multiflow Trace is btw the negative answer posed in the title, it was a successful VLIW compiler), this was the Precision Architecture Wide-Word. You are probably too young to know the entire story. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. Was Itanium a deliberate attempt to make a premium platform and pull the rug out from under AMD, VIA, etc.? The big problem is that when it asked me to run root.sh on both node 1 & 2 it returns Checking to see if Oracle CRS stack is already configured Setting the permissions on OCR backup directory Setting up NS directories Failed to upgrade Oracle Cluster Registry configuration. Leaving optimization to the compiler was a good idea. I guess that their management underestimated the efforts needed to make a compiler. For example, if a processor has all of the following: Where does one find such processors? No one knows if its hardware or software, but it just isn't do-able. I learned a lot about OS reading the ARM reference manual. This made me wonder why exactly this processor is so unpopular and, I think, failed. Well, PowerPC chips are not x86 compatible, but they aren't a fiasco, at least in High Performance Computing. So powerful tool developers still don't use it to its full ability to profile code. It was very hard to write code generators for; and it didn't have much reasons to succeed in the first place (It was made by Intel, so what?). My (admitted unreliable and from someone who followed that from far) recollection is that what HP(*) and Intel failed to achieve on the compiler front is the language level extraction of parallelism, not the low level which would have been present in a byte code. Maybe they were trying to make a premium tier and leave AMD, VIA, etc. DSP. This was challenging for shrink wrapped software vendors and increased the cost/risk of upgrading an Itanium platform to the current generation. by m50d on Monday February 28, 2005 @02:43PM and attached to IBM to Drop Itanium. Getting these right was hard, advanced loads especially! 0 0 1. Their non-VLIW compilers are top-notch, regularly pumping out code much faster than other compilers. BTW, I wished that AMD64 would have been some more RISCy instruction set. (*) You also seem to underestimate HP role in EPIC. The compiler simply can't find independent instructions to put in the bundles. Intel are probably the. I don't think even the Mill team make that claim (their merit factor include power). (That said, if your code makes frequent access to some localized memory areas, caching will help.). A lot of stuff can be done static that otherwise is inefficient in hardware. If multiple instructions are ready to go and they don't compete for resources, they go together in the same cycle. By making their architecture backwards compatible with the x86 instruction set, AMD was able to leverage the existing tools and developer skill sets. In general, there is simply not enough information available at the compile-time to make decisions that could possibly fill up those stalls. Why did the Intel Itanium microprocessors fail? At the time of release software developers were waiting for a decent marketshare before writing software for it and PC buyers were waiting for a decent amount of software before buying. It is possible that the investment in Itanium may have had an enriching effect on the skills of its engineers, which may have enabled them to create the next generation of successful technology. Schedule the following script to decline all Itanium updates. It probably was a bit less true in 1997. How do I place the Clock arrows inside this clock face? I'm not sure why would some one call it a failure when it is generating billions of $ for HP (although it is not just the processor; it is itanium server sales that is generating revenue). And this is where VLIW has flourished. Converting 3-gang electrical box to single. @supercat: I'm not talking about a hypothetical VM, but about a hypothetical IR that would be compiled the rest of the way by an Intel code generator. It failed to set a new standard for PC CPUs, and it failed HP as a suitable replacement for the PA-RISC and Alpha AXP, being outperformed by the end of life designs of both until the Itanium II made up the difference by sheer clock speed brute force. was not that simple; converting a large set of C programs which assumed a 32 bit integer and assumed 32 bit addressing to a native 64 bit architecture was full of pitfalls. EPIC wanted to use the area budget used by the implementation of OOO to provide more raw computing, hoping that compilers would be able to make use of it. I mean, most people. All these above factors slowed adoption of Itanium servers for the mainstream market. If it is in the processor, you have just another micro-architecture and there is no reason not to use x86 as public ISA (at least for Intel, the incompatibility has an higher cost than whatever could bring a cleaner public ISA). They will continue development and announce EPIC in 1997 at the Microprocessor Forum but the ISA won't be released until February 1999 making it impossible to create any tools for it before. - "/g/ - Technology" is 4chan's imageboard for discussing computer hardware and software, programming, and general technology. Dropping backwards compatibility would free up loads of transistor space and allow better instruction mapping decisions to be made. There a new version of Itanium out, the 2500 series. The x86-64 instruction set architecture is really not a "very good" architecture for compiler writer (but it is somehow "good enough"). Sad. Instruction-Level Parallel Processors ). Great points. What prevents a large company with deep pockets from rebranding my MIT project and killing me off? Who doesn't love being #1? I tried to install Oracle Clusterware on 2 hp-ux itanium nodes. It's commonly stated that Intel's Itanium 64-bit processor architecture failed because the revolutionary EPIC instruction set was very difficult to write a good compiler for, which meant a lack of good developer tools for IA64, which meant a lack of developers creating programs for the architecture, and so no one wanted to use hardware without much software for it, and so the platform failed, and all for the want of a horseshoe nail good compilers. Stack Overflow for Teams is a private, secure spot for you and It was slow, but it was there. PAE is the one that the market ended up using (and was extended into the 64-bit era). Performance is still much higher compared to x86. Itanium's simpler design would have pushed more stuff on the compiler (room for growth), allowing to build thinner,faster pipelines. What are the technical reasons behind the “Itanium fiasco”, if any? c) you need some significant improvements to justify an instruction set change like this. However, most general-purpose software must make plenty of random memory accesses. Intel y HP reconocen que Itanium no es competitivo y lo reemplazan por el Itanium 2 un año antes de lo planeado, en 2002. It was also an accident involving a technically inferior product that led directly to a huge monopoly for years. by jhagman on Monday February 28, 2005 @01:20PM and attached to IBM to Drop Itanium. Windows on Itanium has a WoW layer to run x86 applications. Can I (a US citizen) travel from Puerto Rico to Miami with just a copy of my passport? Do they just scrap a decade plus, multibillion project because it's visibly too late? For example, there was a looping feature where one iteration of the loop would operate on registers from different iterations. Does your organization need a developer evangelist? As a former compiler writer, it's true that being able to take an existing compiler back and tweak it for performance is better than writing one all over again. - C++. Itanium (/ aɪ ˈ t eɪ n i ə m / eye-TAY-nee-əm) is a type of Intel microprocessors with 64-bit chip architecture (not related to the by now mainstream 64-bit CPUs made by Intel and others). http://www.cs.virginia.edu/~skadron/cs654/cs654_01/slides/ting.ppt, Itanium's VLIW instruction bundles frequently increased code size by a factor of 3 to 6 compared to CISC, especially in cases when the compiler could not find parallelism. Second, Itanium world (~2001): Updates in processor design and manufacturing can deliver 1.1x speedups. IPF was in-order, for one. As a result, the Itanium failed both Intel and HP’s goals for it. It also isn’t hard to understand why Compaq’s chose Itanium. The third key difference is that implementations of out-of-order processors can be as wide as wanted, without changing the instruction set (Intel Core has 5 execution ports, other processors have 4, etc). And so it is with Itanium. As written above, not only we are still unable -- as AFAIK, even in theory -- to write compilers which have that ability, but the Itanium got enough other hard-to-implement features that it was late and its raw power was not even competitive (excepted perhaps in some niche markets with lots of FP computation) with the other high end processor when it got out of fab. AMD beat Intel at its own game by taking the same evolutionary step from the x86 family that the x86 family did from the 8086/8088 family. I guess is that they did not have enough compiler expertise in house (even if of course they did have some very good compiler experts inside, but probably not enough to make a critical mass). So this initial problem of "chicken and egg" seemed to be solved. What was an issue is the hyper-threading implementation by swapping stacks during memory IO was too slow (to empty and reload the pipeline) until Montecito etc. the 3 instructions/word have been good as long as the processor had 3 functional units to process them, but once Intel went to newer IA64 chips they added more functional units, and the instruction-level parallelism was once again hard to achieve. The architecture allowed Itanium to be relatively simple while providing tools for the compiler to eek out performance from it. What came first, the compiler, or the source? As I mentioned above, part of that dynamic information is due to non-deterministic memory latency, therefore it cannot be predicted to any degree of accuracy by compilers. If anyone does not catch the sense of fatalism from that article, let me highlight this: Load responses from a memory hierarchy which includes CPU caches and DRAM do not have a deterministic delay. Itanium failed because it used a VLIW architecture - great for specialized processing tasks on big machines but for general purpose computing (ie. Many versions of Itanium even has a small x86 CPU inside to run x86 code. Not on Itanium. 2. I don't know why they don't just take x86_64, strip out all 32bit stuff and backwards compatible things like 8087 emulation, mmx etc. Removing intersect or overlap of points in the same vector layer, Building algebraic geometry without prime ideals. Donald Knuth, a widely respected computer scientist, said in a 2008 interview that "the "Itanium" approach [was] supposed to be so terrific—until it turned out that the wished-for compilers were basically impossible to write."1. In this article Jonh Dvorak calls Itanium "one of the great fiascos of the last 50 years". Setters dependent on other instance variables in Java. Can I use deflect missile if I get an ally to shoot me? Processor architecture as a lot to do with programming. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. To make things worse, McKinley was announced back in 1998 with a 2001 shipment date and as this ZDNet article from 1999 March mentions "Word on the street suggests Merced is more likely to be a development platform with few commercial shipments -- most will wait for McKinley". It is not "... (whatever) is hard", it is that EPIC is unsuitable for any platform that has to cope with high dynamism in latency. Itanium failed to make significant inroads against IA-32 or RISC, and suffered further following the arrival of x86-64 systems which offered greater compatibility with older x86 applications. A great answer! Be the first to answer this question. Knuth was saying parallel processing is hard to take advantage of; finding and exposing fine-grained instruction-level parallelism (and explicit speculation: EPIC) at compile time for a VLIW is also a hard problem, and somewhat related to finding coarse-grained parallelism to split a sequential program or function into multiple threads to automatically take advantage of multiple cores. Other machines at the time - namely UltraSPARC - were in-order, but IPF had other considerations too. Why is a third body needed in the recombination of two hydrogen atoms? Non-mainstream RISCs are losing grounds; They didn't see that or hoped it would become mainstream; too bad it wouldn't because there weren't any reasons for that. Is there any reason why Intel didn't specify a "simple Itanium bytecode" language, and provide a tool that converts this bytecode into optimized EPIC code, leveraging their expertise as the folks who designed the system in the first place? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. It could have been some POWERPC64 (but it probably wasn't because of patent issues, because of Microsoft demands at that time, etc...). Of course, with Itanium suffering heavy delays until 2001 (2002 if you discount Merced), SGI were stuck with an architecture for which they had already cancelled future development. By 1993 they decide it's worth developing it into a product and they are looking for a semiconductor manufacturing partner and in 1994 they announce their partnership with Intel. Why do most Christians eat pork when Deuteronomy says not to? It also means yields are lower ... Not until you get into Madison and Deerfield in 2003 do you start talking about volume." like x86. Why was the first compiler written before the first interpreter? Itanium failed because it sucked. This, combined with the existing relative low density, meant that getting a decent i-cache hit rate was a) really important, and b) hard - especially since I2 only had a 16KB L1I (although it was quite fast.). Neither SPARC nor MIPS offers exceptional performance on the type of applications Alpha is good at. There is a second aspect of the failure which is also fatal. Windows Server 2008 R2 builds on the award-winning foundation of Windows Server 2008, expanding existing technology and adding new features to enable organizations to increase the reliability and flexibility of their server infrastructures. The P-system was dog slow compared with what native machine code could do. The Wikipedia article on EPIC has already outlined the many perils common to VLIW and EPIC. Historical background for EPIC instruction set architectures, EPIC: An Architecture for No existing software ran on itanium which was entirely the cause of its downfall. How is Intel killing off all the competition, using a single product line, anything but the greatest microprocessor victory of all time? I've heard some JITs gave worse perfomance than interpreters on Itanium because gcc optimized interpreter better; that's a no-go if a processor requires that level of optimizations. [failed verification] According to Intel, it skips the 45 nm process technology and uses a 32 nm process technology. Convert negadecimal to decimal (and back). Are there any Pokemon that get smaller when they evolve? Update the question so it's on-topic for Stack Overflow. Why is the pitot tube located near the nose? What would seem like a trivial effort for a company offering a software product -- recompile and retest your C code base (and at that time most would have been written in pure C!) It only takes a minute to sign up. better post this before the machune crashes! Itanium designed rested on the philosophy of very wide instruction level parallelism to scale performance of a processor when clock frequency limit is imposed due to thermal constraints. I hope my rephrasing will make the answer to that question obvious. The Intel ITANIUM. More succinctly, Intel vastly underestimated the inertia from those wearing the yoke of backward compatibility. The first Itanium chip was delayed to 2001 and failed to impress most potential customers who stuck to their x86, Power and SPARC chips. What a truly pathetic business model! Compilers have access to optimization info that OOO hardware won't have at run time, but OOO hardware has access to information that is not available to the compiler, It is not that "compiler ... extracting parallelism is hard". Software Engineering Stack Exchange is a question and answer site for professionals, academics, and students working within the systems development life cycle. MIPS, Alpha, PA-RISC -- gone. Thanks. As he mentions near the end, at the mere sight of Itanium, "one promising project after another was dropped". such as unanticipated memory latency costs. What is this “denormal data” about ? Same again when they moved to Core Duo. Those instructions are executed speculatively anyway (based on branch prediction, primarily). AMD was something of a threat but Intel was the king of the hill. It then e-mails an HTML report with the following column headings: Title, KB Article, Classification, Product Title, Product Family The problem was it wasn't one feature, it was many. In reality, prefetching is only profitable if you are performing streaming operations (reading memory in a sequential, or highly predictable manner).

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