[patch] tuning gcc for Intel Core2

H. J. Lu hjl@lucon.org
Mon Nov 13 17:44:00 GMT 2006


On Mon, Nov 13, 2006 at 12:01:17PM -0500, Vladimir Makarov wrote:
>  Here is the patch for tuning gcc for Intel Core2 processor.  I did
> about 30 SPEC2000 runs to find good parameters which are practically
> the same what Intel gave and recommended in their optimization guide
> made public a few days ago.
> 
>  The patch increases SPECINT2000 score to 1963 from 1925 (for
> generic) or 1901 (for nocona).  SPECFP2000 sore is the same as for
> generic 1875 (nocona has 1856).  One benchmark (gcc) did particular
> well -- about 20% improvement (1788 for generic tuning vs 2210 for
> core2).  The size of code generated for Core2 is smaller (0.46% for
> SPECInt and 0.54% SPECFp) than one for generic.

Thanks. Do you happen to have -m32 numbers? We will run 32bit on Core
and Core 2.

> 
>  All measurements were done on 2.66 Ghz Intel Core2 machine.
> 
>  I think DFA for Core2 would increase SPEC scores even more because
> even insn scheduling without the description (using default
> parameters) works well for Core2.  But I have no enough details for
> Core2 to do it.

We are working on Core 2 model. Due to the nature of out-of-order
processor, we aren't sure how much it will help.


H.J.



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