Re: [PATCH] again: Re: Athlon kernel crash (i686 works)

From: VDA (
Date: Wed Oct 10 2001 - 03:09:31 EST

>> I've run several LMbench tests against both 686-optimized
>> and Athlon-optimized kernels. The results waver across multiple
>> tests, one kernel winning some tests one time and losing the next,
>> but the values are all close.

DM> The benefits of the kernel Athlon optimizations are higher memory bandwidth
DM> for bulk copies/clears and less cache pollution. But LMbench isn't going to
DM> show any difference, because its tests use generic x86 mem*() functions, not
DM> Athlon-optimized SSE memory routines like in the Athlon kernel.

There are no SSE optimizations (yet).
There are prefetch/movntq tricks.
Optimized fast_clear_page() is 3x faster than normal one,
optimized fast_copy_page() is 1.5x faster than normal one.
(roughly, it depends on your mem and CPU MHz)

I can mail a test program to you if you are curious.

Best regards, VDA

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