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References: <20231012035111.676789-1-namhyung@kernel.org> <87pm15vw5r.fsf@linux.intel.com>
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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Tue, 24 Oct 2023 12:16:32 -0700
Message-ID: <CAM9d7ch504cnFzTL1qPh349uSrbEZop19kB-DbUsnoOKEvtFBQ@mail.gmail.com>
Subject: Re: [RFC 00/48] perf tools: Introduce data type profiling (v1)
To:     Andi Kleen <ak@linux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-perf-users@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Stephane Eranian <eranian@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        linux-toolchains@vger.kernel.org,
        linux-trace-devel@vger.kernel.org,
        Ben Woodard <woodard@redhat.com>,
        Joe Mario <jmario@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        David Blaikie <blaikie@google.com>,
        Xu Liu <xliuprof@google.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Ravi Bangoria <ravi.bangoria@amd.com>
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Hi Andi,

On Mon, Oct 23, 2023 at 2:58 PM Andi Kleen <ak@linux.intel.com> wrote:
>
> Namhyung Kim <namhyung@kernel.org> writes:
>
> > Hello,
> >
> > I'm happy to share my work on data type profiling.  This is to associate
> > PMU samples to data types they refer using DWARF debug information.  So
> > basically it depends on quality of PMU events and compiler for producing
> > DWARF info.  But it doesn't require any changes in the target program.
> >
> > As it's an early stage, I've targeted the kernel on x86 to reduce the
> > amount of work but IIUC there's no fundamental blocker to apply it to
> > other architectures and applications.
>
> FWIW i posted a similar patchkit a long time ago
>
> https://lore.kernel.org/lkml/20171128002321.2878-13-andi@firstfloor.org/
>
> It was on my list to resurrect that, it's great that you are doing
> something similar.
>
> The latest iteration (not posted) was here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc.git/log/?h=perf/var-resolve-7

Oh, I wasn't aware of this series.  I'll take a look.

>
> The main difference seems to be that mine was more for perf script
> (e.g. i supported PT decoding), while you are more focused on sampling.
> I relied on the kprobes/uprobes engine, which unfortunately was always
> quite slow and had many limitations.

Right, I think dealing with regular samples would be more useful.
But Intel PT support looks interesting.

>
> Perhaps it would be possible merge the useful parts of the two approaches?

Sounds good!  Thanks for your comment!
Namhyung