linux-kernel - Re: [PATCH 0/4] Really lazy fpu

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Message-ID: <4C18B9AC.3070409@redhat.com>
Date:	Wed, 16 Jun 2010 14:46:52 +0300
From:	Avi Kivity <avi@...hat.com>
To:	George Spelvin <linux@...izon.com>
CC:	mingo@...e.hu, linux-kernel@...r.kernel.org, npiggin@...e.de
Subject: Re: [PATCH 0/4] Really lazy fpu

On 06/16/2010 02:32 PM, George Spelvin wrote:
>
> (An halfway version of this optimization whoch sould avoid the need for
> an IPI would be *save* the FPU state, but mark it "clean", so the re-load
> can be skipped if we're lucky.  If the code supported this as well as the
> IPI alternative, you could make a heuristic guess at switch-out time
> whether to save immediately or hope the odds of needing the IPI are less than
> the fxsave/IPI cost ratio.)
>    

That's an interesting optimization - and we already have something 
similar in the form of fpu preload.  Shouldn't be too hard to do.

-- 
error compiling committee.c: too many arguments to function

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