State of AutoFDO in GCC

[Andi Kleen]

172060045@hdu.edu.cn writes:

> Hi all, 
>
> I`m using GCC 9.3 AutoFDO and the old version create_gcov on arm64 
> and it works well. Actually it support not only LBR like mode but 
> also inst_retired even cycles event, which`s the early implementation 
> of AutoFDO[1]. There is no difference in output format of create_gcov 
> between LBR mode and inst_retired. inst_retired is less accurate than 
> LBR but still works.
>
> I hope AutoFDO could work better on GCC and am willing to contribute 
> to it, does anybody have suggestions for me?

I think at a minimum we need someone to run the test suite regularly
and look at all the problem, at least filling PRs, so that regressions
could be fixed.

But I actually hope one of the automatic testers could at least do
the testing.

And perhaps try it on real applications and see how much you can
improve performance, and if there are problems also file PRs.

There's some other work that could be done (e.g. port some of the
missing changes from the old google autofdo tree to mainline), but that
might be more difficult depending on your gcc internals expertise.

-Andi