On Mon, Apr 26, 2021 at 8:12 AM Andi Kleen <a...@linux.intel.com> wrote:
> Jan Hubicka <hubi...@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. > There are multiple directional changes in this new tool: 1) it uses perf-script trace output (in text) as input profile data; 2) it uses pseudo probe like instrumentation FDO to do profile matching; 3) it supports full profile context sensitivity (not just from inline stacks). #1 is most relevant to this discussion -- using text format reduces the pain introduced by perf binary format change. David > > -Andi >
