Re: [PATCH] [RFC] x86 SMP lazy FPU context switching

Adam J. Richter (adam@yggdrasil.com)
Sun, 22 Aug 1999 17:05:19 -0700

About a year ago, I posted a patch to extend the existing
x86 lazy floating point context support to multiprocessor kernels (in
resopnse to a Alan Cox's arguing against having CONFIG_SMP on for
all kernels, because it deactivated lazy FPU support). Shortly
thereafter, x86 lazy FPU support was removed from the kernel
entirely, with some comment about how it did not make much
different on recent x86 processors. I have not been paying attention
lately, but, from your patches, Ben, it looks like some lazy FPU
support has returned.

I am kind of curious: what is the latest thinking on lazy FPU
context loading for x86 these days? Is the pendulum swinging the other
way now? Has anyone done any benchmarks one way or the other?

Adam J. Richter __ ______________ 4880 Stevens Creek Blvd, Suite 104
adam@yggdrasil.com \ / San Jose, California 95129-1034
+1 408 261-6630 | g g d r a s i l United States of America
fax +1 408 261-6631 "Free Software For The Rest Of Us."

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