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Re: [patch] tuning gcc for Intel Core2
- From: "H. J. Lu" <hjl at lucon dot org>
- To: Vladimir Makarov <vmakarov at redhat dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, denis_nagorny at linux dot intel dot com, grigory_zagorodnev at linux dot intel dot com
- Date: Mon, 13 Nov 2006 09:16:10 -0800
- Subject: Re: [patch] tuning gcc for Intel Core2
- References: <4558A4DD.1080407@redhat.com>
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.