Re: State of AutoFDO in GCC

[Wei Mi <wmi@google.com>]

https://github.com/google/autofdo has been updated. Now
create_gcov/dump_gcov are added back and can be built separately.

Please look at "2.2 Build autofdo tool for gcc" in
https://github.com/google/autofdo#readme

On Wed, Apr 28, 2021 at 10:40 PM Andi Kleen <ak@linux.intel.com> wrote:
>
> On Mon, Apr 26, 2021 at 06:40:56PM +0000, Hongtao Yu wrote:
> >    Andi, thanks for pointing out the perf script issues. Can you please
> >    elaborate a bit on the exact issue you have seen? We’ve been using
> >    specific output of perf script such as mmap, LBR and callstack events
> >    filtered by process id. It works fine so far but may certainly hit
issues
> >    in the future with extended uses.
>
> Okay I took a look at the latest autofdo now. It seems to be basically
> a LLVM project now that depends on LLVM to even build with all kinds
> of dependency hell on some old LLVM version and other packages.
>
> I guess gcc will really need a replacement that doesn't pull in
> all of LLVM if it wants to continue supporting autofdo.
>
> I'm myself unable to build now.
>
> I'm using the old version I had a git fork of and that
> was before all of this. I added a patch to make it work
> with the latest perf by ignoring increased perf_attr
> and unknown perf events.
>
> Honza please use
>
> https://github.com/andikleen/autofdo -b perf-future
>
> for testing.
>
> -Andi
>