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From: Vladimir Makarov <vmakarov@redhat.com>
To: Ian Lance Taylor <iant@google.com>
Cc: Jan Dillmann <jan.dillmann@tooltec.de>, gcc-help@gcc.gnu.org
Subject: Re: gcc 3.4.3:  -march optimization for Intel Core2Duo
Date: Thu, 05 Oct 2006 16:08:00 -0000	[thread overview]
Message-ID: <45252DFC.1060505@redhat.com> (raw)
In-Reply-To: <m3r6xmdao5.fsf@localhost.localdomain>

Ian Lance Taylor wrote:

>"Jan Dillmann" <jan.dillmann@tooltec.de> writes:
>
>  
>
>>we are running several benchmarks (SpecCPU200...) on 32-bit linux-systems and are able to set an optimization-parameter
>>for '-march'. We use Intel Core2uo-CPUs. Which parameter should we use (nocona, prescott...) ?
>>    
>>
>
>gcc 3.4.3 has no specific tuning for Core2 Duo, if for no other reason
>than the release was made before the processors became available.  My
>guess would be that you will get the best results with -mtune=nocona.
>But it is only a guess.
>
>  
>
I believe that pentium-m will work better.  Nocona (a x86_64 processor) 
is based on northwood/prescott core which is a high frequency core with 
long pipelines.  Core2 Duo is closer to pentium M (lower frequency core 
with much shorter pipelines).  Although usage of penium-m will result a 
bigger code in comparison with nocona because aligning loop/function 
will be forced (nortwood core is not so sensitive to aligning therfore 
aligining is not done when -mtune=nocona is used).  I don't remember 
Intel recomendation about aligning code for Core Duo (probably it is the 
same as for penium M).

  reply	other threads:[~2006-10-05 16:08 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-05 13:49 Jan Dillmann
2006-10-05 15:50 ` Ian Lance Taylor
2006-10-05 16:08   ` Vladimir Makarov [this message]
2006-10-05 16:26 Timothy C Prince
2006-10-05 16:41 ` Vladimir Makarov
2006-10-07  6:36 ` Ryan Hill

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