[PATCH] Mantaining turnstile aligned to 128 bytes in i386 CPUs
bde at zeta.org.au
Thu Jan 18 10:01:46 UTC 2007
On Wed, 17 Jan 2007, Suleiman Souhlal wrote:
> Bruce Evans wrote:
>> I haven't tried this, but have seen and partly worked sensitivity to
>> linear KVA maps not being physically (non)linear enough. Some CPUs
>> and/or memory systems are remarkably sensitive to bank interleave.
>> FreeBSD's page coloring doesn't know anything about banks, ...
> About page coloring: Don't amd64 CPUs have virtually indexed, physically
> tagged caches? If so, wouldn't it make sense to turn off page coloring,
> since it's useless for virtually indexed caches (and probably hurts things
> a bit)?
I think superpages will soon turn off coloring. Not sure if this is
right. How is copying and zeroing a whole superpage at a time avoided?
IIRC, my benchmarks (and LMbench) show some small positive benefits for
page coloring on amd64. I don't remember exactly what they are, just
that they are smaller than on AthlonXP.
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