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Re: [Fwd: performance with gcc -O0/-O2]

From: Howard Chu <hyc at highlandsun dot com>
To: Richard Guenther <richard dot guenther at gmail dot com>
Cc: gcc at gcc dot gnu dot org
Date: Tue, 27 Nov 2007 08:08:26 -0800
Subject: Re: [Fwd: performance with gcc -O0/-O2]
References: <474C1A62.9000300@highlandsun.com> <84fc9c000711270536i799dc2c7u64d931ebdf213f57@mail.gmail.com>

Richard Guenther wrote:

On Nov 27, 2007 2:23 PM, Howard Chu <hyc@highlandsun.com> wrote:
A bit of a minor mystery. Not a problem, just a curiosity. If someone knew off
the top of their head a reason for it, that'd be cool, but otherwise no sweat.
I'd try -Os, you might run into ICache limitations.

Thanks to everyone for the replies.

Fyi, the runs were all with -march=k8.

The test with gcc 4.2.2 and -Os just finished, it was again faster than -O0 from 4 to 28 clients, but slower than -O0 the rest of the way. It peaked at 38K auths/sec at 120 client threads. Slightly better than -O2. I'll try again with some of these other suggestions. -- -- Howard Chu Chief Architect, Symas Corp. http://www.symas.com Director, Highland Sun http://highlandsun.com/hyc/ Chief Architect, OpenLDAP http://www.openldap.org/project/

References:
- [Fwd: performance with gcc -O0/-O2]
  - From: Howard Chu
- Re: [Fwd: performance with gcc -O0/-O2]
  - From: Richard Guenther

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