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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Tue, 24 Oct 2023 22:51:41 -0700
Message-ID: <CAM9d7cgin9=dh-cypSzpvfZu_N7qv8Gxg0VVGdOm+VXB8i1FAQ@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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On Tue, Oct 24, 2023 at 7:09 PM Andi Kleen <ak@linux.intel.com> wrote:
>
> >
> > >
> > > 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.
>
> My code supported samples too, but only through perf script, not report.
>
> See
>
> https://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc.git/commit/?h=perf/var-resolve-7&id=4775664750a6296acb732b7adfa224c6a06a126f
>
> for an example.
>
> My take was that i wasn't sure that perf report is the right interface
> to visualize the variables changing -- to be really usable you probably
> need some plots and likely something like an UI.

I see.  Your concern is to see how variables are changing.
But it seems you only displayed constant values.

>
> For you I think you focus more on the types than the individual
> variables? That's a slightly different approach.

Right, you can see which fields in a struct are accessed
mostly and probably change the layout for better result.

>
> But then my engine had a lot of limitations, i suppose redoing that on
> top of yours would give better results.

Sounds good, thanks.
Namhyung