linux-kernel - Re: [PATCH] i386-pda UP optimization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <200611151824.36198.ak@suse.de>
Date:	Wed, 15 Nov 2006 18:24:35 +0100
From:	Andi Kleen <ak@...e.de>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Eric Dumazet <dada1@...mosbay.com>, akpm@...l.org,
	Arjan van de Ven <arjan@...radead.org>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] i386-pda UP optimization

On Wednesday 15 November 2006 18:20, Ingo Molnar wrote:
> 
> * Andi Kleen <ak@...e.de> wrote:
> 
> > 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.
> 
> Eric's test shows a 5% slowdown. That's far from cheap.

I have my doubts about the accuracy of his test results. That is why I asked 
him to double check.

-Andi
-
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/