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From: Mel Gorman <mgorman@suse.de>
To: H Peter Anvin <hpa@zytor.com>, Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Mike Galbraith <mgalbraith@suse.de>, Linux-X86 <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/3] Reduce length of the eagerfpu path during x86 context switches
Date: Wed, 27 Aug 2014 17:03:35 +0100	[thread overview]
Message-ID: <20140827160335.GD12424@suse.de> (raw)
In-Reply-To: <1407329748-3928-1-git-send-email-mgorman@suse.de>

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?

Thanks

-- 
Mel Gorman
SUSE Labs

  parent reply	other threads:[~2014-08-27 16:03 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-06 12:55 [PATCH 0/3] Reduce length of the eagerfpu path during x86 context switches Mel Gorman
2014-08-06 12:55 ` [PATCH 1/3] x86, fpu: Do not copy fpu preload state Mel Gorman
2014-08-06 12:55 ` [PATCH 2/3] x86, fpu: Split FPU save state preparation into eagerfpu and !eagerfpu parts Mel Gorman
2014-08-06 12:55 ` [PATCH 3/3] x86, fpu: Do not update fpu_counter in the eagerfpu case Mel Gorman
2014-08-27 16:03 ` Mel Gorman [this message]
2014-08-27 17:03   ` [PATCH 0/3] Reduce length of the eagerfpu path during x86 context switches H. Peter Anvin
  -- strict thread matches above, loose matches on Subject: below --
2014-08-06 12:55 Mel Gorman

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