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Itanium and MIPS were... just fine though. Both architectures have parts that were very competitive along essentially all metrics the market cares about. ia64
by ajross 3y ago
Itanium and MIPS were... just fine though. Both architectures have parts that were very competitive along essentially all metrics the market cares about. ia64 failed for compatibility reasons, and because it wasn't "faster enough" than x86_64. No one saw much of a reason to run it, but Intel made them well and they made them fast.
And MIPS failed for the same reason ARM pulled ahead: in the late 90's Intel took a huge (really, huge) lead over the rest of the industry in process and MIPS failed along with basically every other CPU architecture of the era
Amusingly the reason ARM survived this bottleneck is because it was an "embedded" architecture in a market Intel wasn't targetting. But there's absolutely nothing technical that would prevent us from running very performant MIPS Macs or whatever in the modern world.
- cpgxiii 3y agoItanium failed in the market because it wasn't fast enough running general purpose code (HPC workloads were a different story). As a consequence, it's ability to run existing x86 code was poor (both in hardware and software emulation). At the root, Itanium's poor performance was a direct consequence of the design assumption that a sufficiently smart compiler could extract sufficient instruction-level parallelism. While the ISA didn't prohibit later improvements like OoO execution, it always required a better compiler (and more specific workloads) than real users would have.
- pjmlp 3y agoItanium failed in the market because AMD was allowed to come up with AMD64, that is all. Had it not been the case, the market would have been driven to Itanium no matter what.
- ghaff 3y agoItanium was never really "just fine." The performance (or complete lack thereof) of x86 compatibility mode was one problem. But VLIW's reliance on software to do the right thing (with compilers etc.) was another big thing even for native IA64 code. And a decent-performing Itanium was delayed enough to arrive during dot-bomb vs. dot-com. If Itanium had really been the only 64-bit chip available for use in systems from multiple vendors maybe it would have succeeded by dint of an Intel monopoly position. But once x86_64 arrived from AMD and Intel ended up following suit, it was pretty much game over for Itanium.
- ajross 3y agoThat's kinda revisionist. In fact ia64 owned the FP benchmark space for almost a decade, taking over from Alpha and only falling behind P6 derivatives once those started getting all the high end process slots (itself because Intel was demolishing other manufacturers in the high-margin datacenter market). The point was that ia64 was certainly not an "inferior" ISA, It did just fine by any circuit-design measure you want. Like every other ISA, it failed in the market for reasons other than logic design.
- ghaff 3y agoItanium had some specific performance strong points. FP was one. Certain types of security code was another. In fact (and I may have the details somewhat wrong) but an HP CTO co-founded a security startup, Secure64?, on the back of Itanium security code performance. But logic design is irrelevant beyond a certain point. Intel certainly had the process chops at the time and knew how to design microprocessors given a certain set of parameters. It's just the parameters were wrong (see Intel's late step-down from frequency on x86 above all else as well--driven I was told at a very high level by Microsoft's nervousness around multicore).
- jandrese 3y agoFP benchmarks are just about the most synthetic benchmarks there are though. They mostly matter to people doing HPC, and those kinds of workloads are often in the realm of supercomputers. Which I think means everybody is saying basically the same thing, ia64 was overly specialized and had far too small of a market niche to survive.
- LgWoodenBadger 3y agoFP performance seems completely orthogonal to ISA superiority/inferiority. And I doubt the exceedingly-advanced compiler that the Itanium ISA required contributed in any way to its fp performance.
- CamperBob2 3y agoThat's kinda revisionist. No, that's pretty much exactly what happened. Were you there? Beating everyone else at synthetic benchmarks is about as impressive as blowing away paper targets at the firing range. Real applications (and their operating systems) shoot back.
- aleph_minus_one 3y agoBeside the mentioned points concerning the Itanium, there was another one that is important to consider: the Itanium was simply too expensive for many customers/applications (think: "typical" companies who buy PCs so that their employees can use them for office work; private PC users who might be enthusists, but are not that deep-pocketed; ...).
- lstodd 3y agoARM owned the mobile market with ARM7 TDMI cores/socs back then. That's what allowed them to survive. Itanium on the other hand was killed by x86_64, yes.