[PATCH] D136846: [Driver] Add -fsample-profile-use-profi

Thu Nov 3 02:24:57 PDT 2022

HaoyuZhang added inline comments.

================
Comment at: clang/include/clang/Driver/Options.td:1254
+    HelpText<"Use profi to infer block and edge counts.">,
+    DocBrief<[{Profi - a flow-based profile inference algorithm is an extended
+               and significantly re-engineered classic MCMF (min-cost max-flow)
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hans wrote:
> HaoyuZhang wrote:
> > hans wrote:
> > > I have to say, just reading this text I don't understand what it does.
> > > 
> > > I think a good description would start with "Infer block and edge counts " and then some kind of summary of how it does that.
> > > 
> > > I assume profile info is still needed for this (that's the input, right?) That should probably also be explained, and maybe we should warn when using -fsample-profile-use-profi without -fprofile-sample-use?
> > > 
> > > 
> > > My main concern is that there's no documentation for this. How is a user supposed to learn about this feature and how it works? Why can't someone add something to https://clang.llvm.org/docs/UsersManual.html#profile-guided-optimization ? Once that is figured out, describing what the option does will probably be easy.
> > Sorry for the unclear description of the DocBrief and I have do some modification. 
> > 
> > A checking has been added for ensuring that -fsample-profile-use-profi is only allowed with fprofile-sample-use. Otherwise, there will be an error.
> > 
> > About the document in above link, do you want me to add some contents about using profi after the patch or invite the author of profi?
> It would ideally be added in this patch. Inviting the author of profi (I didn't realize it was a different person) sounds like a good idea.
Hi Hans, I have added the documentation about profi in this patch and also invited the author to take a look. 

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D136846/new/

https://reviews.llvm.org/D136846