Re: GCC-4.5.0 comparison with previous releases and LLVM-2.7 on SPEC2000 for x86/x86_64

[Xinliang David Li <davidxl at google dot com>]

On Tue, Nov 16, 2010 at 6:35 AM, Jan Hubicka <hubicka@ucw.cz> wrote:
>> More FDO related performance numbers
>>
>> Experiment 1: ?trunk gcc O2 + FDO vs O2: ? ? ?FDO improves performance
>> by 5% geomean
>> Experiment 2: our internal gcc compiler (4.4.3 based with many local
>> patches) O2 + FDO vs O2 (trunk gcc): ? FDO improves perf by 6.6%
>> geomean
>> Experiment 3: our internal gcc (4.4.3 with local patchs) O2 + LIPO vs
>> O2 (trunk gcc): ?LIPO improves by 12%
>> Experiment 4: trunk gcc O2 + LTO + fwhole-program + FDO vs O2: ?LTO +
>> FDO improves by 10.8%
>>
>>
>> 1. Trunk gcc FDO vs O2 ?(5%)
>>
>> ? ? ? ? ? ? 164.gzip ? ? ? ? ? ? ? ?1324 ? ? ? ? ? ? ? ?1302 ? ? -1.64%
>> ? ? ? ? ? ? ?175.vpr ? ? ? ? ? ? ? ?1694 ? ? ? ? ? ? ? ?1725 ? ? ?1.84%
>> ? ? ? ? ? ? ?176.gcc ? ? ? ? ? ? ? ?2293 ? ? ? ? ? ? ? ?2387 ? ? ?4.07%
>> ? ? ? ? ? ? ?181.mcf ? ? ? ? ? ? ? ?1772 ? ? ? ? ? ? ? ?1756 ? ? -0.88%
>> ? ? ? ? ? 186.crafty ? ? ? ? ? ? ? ?2320 ? ? ? ? ? ? ? ?2280 ? ? -1.75%
>> ? ? ? ? ? 197.parser ? ? ? ? ? ? ? ?1166 ? ? ? ? ? ? ? ?1556 ? ? 33.42%
>> ? ? ? ? ? ? ?252.eon ? ? ? ? ? ? ? ?2443 ? ? ? ? ? ? ? ?2552 ? ? ?4.45%
>> ? ? ? ? ?253.perlbmk ? ? ? ? ? ? ? ?2410 ? ? ? ? ? ? ? ?2586 ? ? ?7.28%
>> ? ? ? ? ? ? ?254.gap ? ? ? ? ? ? ? ?1987 ? ? ? ? ? ? ? ?2021 ? ? ?1.71%
>> ? ? ? ? ? 255.vortex ? ? ? ? ? ? ? ?2392 ? ? ? ? ? ? ? ?2720 ? ? 13.71%
>> ? ? ? ? ? ?256.bzip2 ? ? ? ? ? ? ? ?1719 ? ? ? ? ? ? ? ?1717 ? ? -0.12%
>> ? ? ? ? ? ?300.twolf ? ? ? ? ? ? ? ?2288 ? ? ? ? ? ? ? ?2331 ? ? ?1.86%
>>
>> 2. 4.4.3 gcc with local patch FDO vs trunk O2 (6.6%)
>
> Interesting, any idea from where this 1.6% is comming?

Probably due to local patches (inliner, lrs, etc) we have, but I have
not studied it.

> ?I guess LIPO this might
> be also reason for that 2% difference in LIPO results (in general LTO
> -fwhole-program + FDO should be stronger, but it is not tunned at all yet).
>
> Since the LIPO branch was updated to mainline some time ago, it would be nice
> to compare the LIPO from the branch with mainline LTO. ?i guess more fair comparsion
> should be O2+FDO+LTO WRT O2+LIPO as LIPO makes no whole program assumptions
> at all, right?

Yes. Raksit maintains the upstream lipo branch, but it has not been
tuned for performance yet.  We have open sourced our compiler changes
via android. It is better to use that  if any one is interested.

Thanks,

David


>
> Honza
>