On 09/07/2011 12:23 PM, Vladimir Makarov wrote:
On 09/07/2011 11:55 AM, Xinliang David Li wrote:
Why is lto/whole program mode not used in LLVM for peak performance
comparison? (of course, peak performance should really use FDO..)
Thanks for the feedback. I did not manage to use LTO for LLVM as it
described on
http://llvm.org/docs/LinkTimeOptimization.html#lto
I am getting 'file not recognized: File format not recognized' during
the linkage pass.
You probably right that I should use -Ofast without -flto for gcc
then. Although I don't think that it significantly change GCC peak
performance. Still I am going to run SPEC2000 without -flto and post
the data (probably on the next week).
As for FDO, unfortunately for some tests SPEC uses different training
sets and it gives sometimes wrong info for the further optimizations.
I do not look at this comparison as finished work and am going to run
more SPEC2000 tests and change the results if I have serious
reasonable objections for the current comparison.
I've add -Ofast without -flto -fwhole-program for GCC as well and
updated the graphs:
http://vmakarov.fedorapeople.org/spec/
