On Fri, Apr 23, 2021 at 7:28 AM Xinliang David Li via Gcc <gcc@gcc.gnu.org> wrote: > > Hi, the create_gcov tool was probably removed with the assumption that it > was only used with Google GCC branch, but it is actually used with GCC > trunk as well. > > Given that, the tool will be restored in the github repo. It seems to build > and work fine with the regression test. > > The tool may ust work as it is right now, but there is no guarantee it > won't break in the future unless someone in the GCC community tries to > maintain it.
I think if we want to keep the feature it makes sense to provide create_gcov functionality either directly from perf (input data producer) or from gcc (data consumer). Of course I have no idea about its complexity, license or implementation language ... 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 > > > > > > > > >
