linux-kernel - Re: [PATCH] x86: introduce and use percpu

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Message-ID: <4BCFF12D.60007@zytor.com>
Date:	Wed, 21 Apr 2010 23:48:13 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jan Beulich <jbeulich@...ell.com>
CC:	mingo@...e.hu, tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: introduce and use percpu_inc()

On 04/21/2010 11:26 PM, Jan Beulich wrote:
> 
>> Keep in mind that although INC is smaller than ADD,
>> the former has flag dependencies that the latter doesn't...
> 
> Wasn't that a problem just on Pentium4-s, which when I submitted
> another related patch a couple of months back I was told would
> not be a primary target anymore?
> 

It doesn't look like it, from what I could tell after the abovementioned
conversation... I was wondering mostly how many bytes this saved across
the kernel.  If it saves a byte in one place it's not so interesting,
but if it is all over it might make more sense.

It bit much worse on P4 than on most other cores, though.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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