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Linus Has Harsh Words For Itanium
Anonymous Coward writes "As a follow up to the earlier story "Intel: No Rush to 64-bit Desktop"... In words that Intel are likely to be far from happy with, the Finnish luminary has stuck the boot into Itanium. His responses to some questions on processor architecture are sure to be music to AMD's ears. Linus, in an Inquirer interview concludes: "Code size matters. Price matters. Real world matters. And ia-64... falls flat on its face on ALL of these."" Of course, Linus works for a chip maker ;)
Torvalds is no longer to be trusted. His position as a profitmaking employee of a money-losing corporation nullifies his credibility.
- Intel is a company that time and time again proves it knows how to make money.
Yeah, by relegating each successive x86 architecture to the role of "back up plan" and pushing forward some "new idea" like i432, i860/i960, and now Itanium.The fact is, although their formula for success is so god damned bloody obvious (sell more x86s) they only managed to realize this almost by accident.
- Sure there are lots of difficulties going to a new ISA.
And as any other CPU endeavour will attest, you can't fix the ISA, except to add instructions in afterwards (and even then you have "legacy applications" problems.)- Especially at the server level. And yes Itanium has had some performance problems, especially in its first revision, but then again when was the last time you saw a company produce a 1st generation microprocessor and have it do well?
Alpha? Sparc? MIPS? All of them topped the performance charts when they were first introduced, and typically by margins *much* higher than Itanium 2's current FP lead in Spec FP.- IA64 offers tons of advanced ILP concepts and OS concepts that, when correctly implemented, can increase performance drastically.
Yeah unfortunately it requires that you write your software in a completely different way, or have compilers using "the hand of god" techniques.- (if your looking for examples, data speculation,
Something available from transmeta's CPUs.- control speculation,
More commonly referred to as "branch prediction".- predication,
Conditional moves -- yawn.- registers with kernel access only,
Are you sure that this is unique to IA-64? We know for a fact that x86-64 will at the very least, reserve FS and GS for ring-0 access.- rotating register files,
As opposed to the more general "renamed registers".- The problem may be, it puts a lot of complexity into the Compilers, and compiler technology isn't good enough for Itanium yet.
Has it occurred to you that perhaps it *cannot* get good enough? The results you see are the most herculean efforts from the combined HP and Intel compiler teams. Its not like there is some magical compiler solution -- they already have state of the art in compiler technology in what they have today.