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Re: 40% performance regression SPEC2006/leslie3d on gcc-4_2-branch
> Grigory Zagorodnev wrote:
> > Mark Mitchell wrote:
> >> Excellent question; I should have asked for that as well. If 4.2 has
> >> gained on 4.1 in other respects, the 4.7% drop might represent a smaller
> >> regression relative to 4.1.
> >>
> > There is the 4.2 (r120817) vs. 4.1.2 release FP performance comparison
> > numbers. SPECfp_base2006 of gcc 4.2 has 19% performance gain over 4.1.2.
>
> Thank you for the measurements.
>
> In that case, I think we have absolutely nothing to worry about for
> 4.2.0. Whether we deliver 19% SPECfp, 23% SPECfp, or 15% SPECfp
> improvements isn't so important; all of those numbers are a vast
> improvement over 4.1.x. Given that, I think we should just leave
> Danny's conservative changes in, and not worry.
It should be understood that the large improvement on Cores is special
case caused by adding a generic model and CPU specific tuning (We
originally measured 28% speedup on P4 and SPECfp2000 just for that
change). Situation can be less optimistic on other (sub)targets.
Still we made important progress on SPECfp in the 4.x series, so 4%
slowdown would not bring us to performance of GCC's from mid 90's as 4%
slowdown on SPECint would perhaps do...
Honza
>
> Thanks,
>
> --
> Mark Mitchell
> CodeSourcery
> mark@codesourcery.com
> (650) 331-3385 x713