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Reply-To: sedat.dilek@gmail.com
From:   Sedat Dilek <sedat.dilek@gmail.com>
Date:   Fri, 22 Jan 2021 02:51:09 +0100
Message-ID: <CA+icZUVdM_mOMwp6V=jwj0422uaRUMHKQMkSkFScgbWqynS+iA@mail.gmail.com>
Subject: Re: [PATCH v6] pgo: add clang's Profile Guided Optimization infrastructure
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Bill Wendling <morbo@google.com>, Jonathan Corbet <corbet@lwn.net>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Sami Tolvanen <samitolvanen@google.com>
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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 -