Re: [PATCH v6] pgo: add clang's Profile Guided Optimization infrastructure

Sedat Dilek
2021-01-22T01:52:06Z

On Fri, Jan 22, 2021 at 2:44 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> On Thu, Jan 21, 2021 at 2:35 AM Sedat Dilek <sedat.dilek@gmail.com> wrote:
> >
> > Thanks for v6.
> >
> > Small Changelog nits:
> > * Can you reverse-order the changelog - latest v6 first.
> > * v4: s/Makfile changes and se/Ma*k*efile changes and *u*se
> >
> > Can you add a hint to this "Clang-PGO" patch requiring Clang >= 12?
> >
> > Can you please add a comment for people using Clang >= 12 (ToT) and
> > have kernel-modules enabled, they will need the patch from CBL issue
> > #1250?
> > Otherwise they cannot boot and follow the next steps in the workflow.
> >
> > Can you put a comment about value "1" to reset the profiling counter?
> > That there is no "0" value stopping it.
> >
> > Can you add an example for the workload test?
> > Here I do a x86-64 defconfig build.
> > See attached script.
> >
> > Usually, I download this patch from LORE.
> >
> > link="https://lore.kernel.org/r/20210111081821.3041587-1-morbo@google.com"
> > b4 -d am $link
> >
> > This downloads v6.
> >
> > What if I want a previous version (compare)?
> > Again, I will love to see a "clang-pgo" branch and maybe tags for the
> > several versions in your personal GitHub.
> > Come on, Bill :-).
>
> That's quite a long list, Sedat! Do you think some of these can be
> follow ups, once the core lands? I'd much prefer to land the meat of
> this and follow up quickly, than tire out poor Bill! :P
>

Poor Bill - he lost his hairs :-)?

I hoped that the documentation gets a bit improved and clearer at some places.

- Sedat -