From: "Ingo at Pyrillion" <ingo@pyrillion.org>
To: "'Norberto Bensa'" <norberto+linux-kernel@bensa.ath.cx>
Cc: <linux-kernel@vger.kernel.org>
Subject: AW: Kernel 2.6.3 patch for Intel Compiler 8.0
Date: Wed, 10 Mar 2004 01:18:03 +0100
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I used the patch to compile two identical kernels with gcc 3.3.3 and
icc 8.0 with oprofile support built in.
The optimization switches were chosen quite conservative, i.e.
"-O2 -Ob1", no IPO, and of course: no MMX, SSE, and SSE2 stuff inside
the kernel (thus disabling Intel's great vectorizer).
Profiling: lmbench ran ten times but time measurements were taken from
oprofile (on Pentium 4, GLOBAL_POWER_EVENTS in kernel space only, 
counter overflow: 3.000).
Results: 33% of the lmbench procs faster on icc, 66% faster on gcc.

Thus, take the kernel patch as a good basis for modifying the 
compiler switches and other things to get more performance gains. As
I know, a lot of people are looking for a patch.

Please check the patch file; you have to modify a lot of things in 2.6.3
to create a quite stable working version of the kernel. The patch is not
just about changing some minor Makefile things...

Kind rgs., Ingo.

-----Urspr?ngliche Nachricht-----
Von: Norberto Bensa [mailto:norberto+linux-kernel@bensa.ath.cx] 
Gesendet: Mittwoch, 10. M?rz 2004 01:09
An: Ingo at Pyrillion
Cc: linux-kernel@vger.kernel.org
Betreff: Re: Kernel 2.6.3 patch for Intel Compiler 8.0


Ingo at Pyrillion wrote:
> patch to compile the kernel with Intel Compiler 8.0
> for Linux.

Speed improvements over same kernel compiled with gcc?

Thanks,
Norberto

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