Messages in this thread | | | Date | Thu, 1 May 2003 22:14:25 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [RFC][PATCH] Faster generic_fls |
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On 1 May 2003, David S. Miller wrote: > > This actually is false. GCC does not know what resources the > instruction uses, therefore it cannot perform accurate instruction > scheduling.
Yeah, and sadly the fact that gcc-3.2.x does better instruction scheduling has shown itself to not actually _matter_ that much. I'm quite impressed by the new scheduler, but gcc-2.x seems to still generate faster code on too many examples.
CPU's are getting smarter, not dumber. And that implies, for example, that instruction scheduling matters less and less. What matters on the P4, for example, seems to be the _choice_ of instructions, not the scheduling of them.
Linus
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