Messages in this thread | | | Date | Mon, 8 Sep 2008 12:55:25 -0700 | From | Arjan van de Ven <> | Subject | Re: [git pull] x86 fixes |
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On Mon, 8 Sep 2008 12:30:02 -0700 (PDT) Linus Torvalds <torvalds@linux-foundation.org> wrote: > > I think there are realistically three classes: > > - _really_ old, to the point of being totally useless for SMP. > > This is really just 386 and clones. We _need_ a working WP for a > race-free access_ok(), and we need cmpxchg (and lately xadd). > > Smaller pains even on UP: bswap doesn't exist. invlpg doesn't > exist.
I'd lump all cpus that don't have cpuid in this bucket too (eg half the 486es) simply because not having cpuid is painful in pretty much the same way.
> - old. pre-cmov. i486 and pentium, and some clones.
makes sense
> - "modern 32-bit": PPro and better. Can take CMOV, MMX and TSC for > granted.
again makes sense; question is if it makes sense to take PSE and PAE for granted as well (although PSE we can do runtime I suppose)
> Hmm? Doesn't that sound like a sane model?
it does to me; the only question is if we hit a new bucket with the various fancy string instructions that are in upcoming models; doing string/copy operations inlined for those guys will make a fourth bucket.
-- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org
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