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From: Andi Kleen <ak@suse.de>
To: Eric Dumazet <dada1@cosmosbay.com>
Subject: Re: [PATCH] i386-pda UP optimization
Date: Wed, 15 Nov 2006 12:32:31 +0100
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On Wednesday 15 November 2006 12:27, Eric Dumazet wrote:
> Seeing %gs prefixes used now by i386 port, I recalled seeing strange oprofile 
> results on Opteron machines.
> 
> I really think %gs prefixes can be expensive in some (most ?) cases, even if 
> the Intel/AMD docs say they are free.

They aren't free, just very cheap.

> 
> With the attached patch, I got 12.212 s, and a kernel text size reduction of 
> 3400 bytes.

Are the benchmark numbers stable? i.e. if you repeat them multiple times
with reboots do you still get the same difference?

-Andi