On 2019-07-09 23:11 +0100, Ken Moffat via blfs-dev wrote: > I've now completed a real "tuning" run of my experiment (i.e. > specifying -falign-functions=32 -malign-data=cacheline because these > have been said to be beneficial for haswell processors, which is > what I have been using. > > Summary in > http://www.linuxfromscratch.org/~ken/tuning/tuning-4-alignment-tests.txt > and updated spreadsheet of the tests I was able to run 10 times on > the different builds: > > (desktop-runtime-comparisons.ods in the same directory). > > Conclusion for this experiment: case not proven. > > I hope to get one more run done ("turn all the optimization up to > -O3") but I will not be playing with alignment again. > > Also, I had hoped to examine LTO (and I might take a stab at the > first part of that - my previous attempt at recompiling gcc > was a disaster in its testsuite, but maybe that was because I had > not understood the problem of using -D_FORTIFY_SOURCE=2 on gcc at > that point). However, the big gains touted for LTO (smaller > programs) come at a compile time cost - for those of us who > frequently rebuild I'm not at all sure that the cost will be > worthwhile.
I only build GCC with LTO using --with-build-config=bootstrap-lto. There are annoying problems with LTO and shared objects with ".symver" directive so I never use LTO for other packages. You may want to consult https://github.com/InBetweenNames/gentooLTO . -- Xi Ruoyao <xry...@mengyan1223.wang> School of Aerospace Science and Technology, Xidian University -- http://lists.linuxfromscratch.org/listinfo/blfs-dev FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page
