State of AutoFDO in GCC

[Andi Kleen]

Jan Hubicka <hubicka@ucw.cz> writes:
>
> Is there a way to get this working w/o using older perf?

It's usually rather simple to fix up autofdo for new perf.
I did it before here

https://github.com/andikleen/autofdo/commits/perf4-3

I think it would work always if it just ignored unknown records
(which is quite possible). perf adds new records now and then,
but they can be usually ignored by old tools.
Only the assert happy coding style in autofdo prevents it.

BTW longer term my feeling is autofdo should be replaced with something
like https://lists.llvm.org/pipermail/llvm-dev/2020-August/144101.html
I think that would fix most of the weirdnesses in the current autofdo
implementation.

-Andi