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Message-Id: <1407329748-3928-1-git-send-email-mgorman@suse.de> Date: Wed, 6 Aug 2014 13:55:45 +0100 From: Mel Gorman <mgorman@...e.de> To: H Peter Anvin <hpa@...or.com>, Suresh Siddha <suresh.b.siddha@...el.com> Cc: Mike Galbraith <mgalbraith@...e.de>, Linux-X86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>, Mel Gorman <mgorman@...e.de> Subject: [PATCH 0/3] Reduce length of the eagerfpu path during x86 context switches 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. arch/x86/include/asm/fpu-internal.h | 46 +++++++++++++++++++++++++++++-------- arch/x86/kernel/process_32.c | 2 +- arch/x86/kernel/process_64.c | 2 +- 3 files changed, 38 insertions(+), 12 deletions(-) -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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