Re: State of AutoFDO in GCC

["Bin.Cheng" <amker.cheng@gmail.com>]

On Fri, Apr 23, 2021 at 4:16 AM Martin Liška <mliska@suse.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?
Hi Martin,
I haven't touched this part for quite some time.  I have no objection
to removing it from GCC.  However, I do have general concern that
because of fewer users/developers, it's less likely and harder for new
features to land in GCC.  I have no idea if this is a real problem or
how to fix it.  OTOH, maybe removing rotten features, making GCC
more(?) concise, and improving existing features that GCC is doing
well is the right thing.

Thanks,
bin
>
> Martin
>
> >
> > Thanks,
> >
> > Eugene
> >
>