On Fri, Apr 23, 2021 at 10:16 AM Jan Hubicka <hubi...@ucw.cz> wrote: > > > > It uses create_llvm_prof tool which is in the same git repo. The data > > parsing part is shared with create_gcov, but the writer is obviously > > different for the two tools. > > OK and what are the main differences between llvmand gcc format? > > GCC expects GCOV format, I think while LLVM uses a newly designed binary format.
David > Honza > > > > David > > > > > > > Honza > > > > > > > > David > > > > > > > > > > > > > > Thoughts? > > > > > Martin > > > > > > > > > > > > > > > > > Having the tool third-party makes keeping the whole chain working > > > more > > > > > > difficult. > > > > > > > > > > > > Richard. > > > > > > > > > > > >> Thanks, > > > > > >> > > > > > >> David > > > > > >> > > > > > >> On Thu, Apr 22, 2021 at 3:29 PM Jan Hubicka <hubi...@ucw.cz> > wrote: > > > > > >> > > > > > >>>> On 4/22/21 9:58 PM, Eugene Rozenfeld via Gcc wrote: > > > > > >>>>> GCC documentation for AutoFDO points to create_gcov tool that > > > > > converts > > > > > >>> perf.data file into gcov format that can be consumed by gcc > with > > > > > >>> -fauto-profile ( > > > > > https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html, > > > > > >>> https://gcc.gnu.org/wiki/AutoFDO/Tutorial). > > > > > >>>>> > > > > > >>>>> I noticed that the source code for create_gcov has been > deleted > > > from > > > > > >>> https://github.com/google/autofdo on April 7. I asked about > that > > > > > change > > > > > >>> in that repo and got the following reply: > > > > > >>>>> > > > > > >>>>> > > > https://github.com/google/autofdo/pull/107#issuecomment-819108738 > > > > > >>>>> > > > > > >>>>> "Actually we didn't use create_gcov and havn't updated > > > create_gcov > > > > > for > > > > > >>> years, and we also didn't have enough tests to guarantee it > works > > > (It > > > > > was > > > > > >>> gcc-4.8 when we used and verified create_gcov). If you need > it, it > > > is > > > > > >>> welcomed to update create_gcov and add it to the respository." > > > > > >>>>> > > > > > >>>>> Does this mean that AutoFDO is currently dead in gcc? > > > > > >>>> > > > > > >>>> Hello. > > > > > >>>> > > > > > >>>> Yes. I know that even basic test cases have been broken for > years > > > in > > > > > the > > > > > >>> GCC. > > > > > >>>> It's new to me that create_gcov was removed. > > > > > >>>> > > > > > >>>> I tend to send patch to GCC that will remove AutoFDO from GCC. > > > > > >>>> I known Bin spent some time working on AutoFDO, has he came > up to > > > > > >>> something? > > > > > >>> > > > > > >>> The GCC side of auto-FDO is not that hard. We have most of > > > > > >>> infrastructure in place, but stopping point for me was always > > > > > difficulty > > > > > >>> to get gcov-tool working. If some maintainer steps up, I > think I > > > can > > > > > >>> fix GCC side. > > > > > >>> > > > > > >>> I am bit unsure how important feature it is - we have FDO that > > > works > > > > > >>> quite well for most users but I know there are some users of > the > > > LLVM > > > > > >>> implementation and there is potential to tie this with other > > > hardware > > > > > >>> events to asist i.e. if conversion (where one wants to know how > > > well > > > > > CPU > > > > > >>> predicts the jump rather than just the jump probability) which > I > > > always > > > > > >>> found potentially interesting. > > > > > >>> > > > > > >>> Honza > > > > > >>>> > > > > > >>>> Martin > > > > > >>>> > > > > > >>>>> > > > > > >>>>> Thanks, > > > > > >>>>> > > > > > >>>>> Eugene > > > > > >>>>> > > > > > >>>> > > > > > >>> > > > > > > > > > > > > > >
