Messages in this thread | | | Date | Wed, 27 Aug 2014 10:03:02 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 0/3] Reduce length of the eagerfpu path during x86 context switches |
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On 08/27/2014 09:03 AM, Mel Gorman wrote: > On Wed, Aug 06, 2014 at 01:55:45PM +0100, Mel Gorman wrote: >> Eager FPU switching is used on CPUs that support xsave on the grounds >> that CPUs that support it can optimise the switch with xsaveopt and xrstor >> instead of serialising by updating cr0.TS which has serialising semantics. >> >> The path for eagerfpu is fatter than it needs to be because it still >> maintains the fpu_counter for lazy FPU switches even though the information >> is never used. This patch splits the paths optimises the eagerfpu path a >> little. The benefit is marginal, it was just noticed when looking at why >> integer-only workloads were spending time saving/restoring FPU states. >> > > This was initially sent when it would collide with the merge window > which was stupid timing. Nothing has actually changed since but I wonder > if anyone had a chance to take a look at this patches? >
Looking at it now.
-hpa
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