[PATCH] D145171: [FSAFDO] Improve FS discriminator encoding

[Wenlei He via Phabricator via llvm-commits]

wenlei added a comment.

> There is also a small change on the create_llvm_prof tool side. We will update the tool soon.

What kind of change is that about? Appreciate if you could drop us a note when the change is up since we don't closely follow create_llvm_prof updates.

> BTW, I'll started the integration with CSSPGO base off here. Pseudo probes have a potential to allow more bits for the FS discriminator and additional FS passes. Implementation-wise, the potential comes from placing the FS discriminator field as a separate int64 operand of the pseudo probe intrinsic, instead of using the existing dbg metadata. I would like your thoughts about whether it's worth the diversion. Thanks.

All thing being equal, I'd favor consistency. But there's potential benefit by allowing more FS profile loading, though whether that is material depends on whether we will actually leverage the ability to load more than 4 profiles. My intuition is that loading base profile + pre-RA profile + pre-layout profile as the way it is today is probably good enough.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D145171/new/

https://reviews.llvm.org/D145171