From: Artem Savkov <asavkov@redhat.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Milian Wolff <milian.wolff@kdab.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>
Subject: Re: [PATCH 0/1] perf report: append inlines to non-dwarf callchains
Date: Tue, 4 Apr 2023 08:58:07 +0200 [thread overview]
Message-ID: <20230404065807.GB56712@samus.usersys.redhat.com> (raw)
In-Reply-To: <CAM9d7cgOA97n10FPz0Bwjtmfon1En+CN2K7CYL3fQ6nrjBqF9Q@mail.gmail.com>
On Mon, Apr 03, 2023 at 10:47:37PM -0700, Namhyung Kim wrote:
> On Mon, Apr 3, 2023 at 1:30 PM Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> >
> > Em Fri, Mar 31, 2023 at 10:52:24AM +0200, Artem Savkov escreveu:
> > > On Thu, Mar 30, 2023 at 08:06:20AM +0300, Adrian Hunter wrote:
> > > > On 22/03/23 21:44, Arnaldo Carvalho de Melo wrote:
> > > > > Em Wed, Mar 22, 2023 at 11:18:49AM -0700, Namhyung Kim escreveu:
> > > > >> On Fri, Mar 17, 2023 at 12:41 AM Artem Savkov <asavkov@redhat.com> wrote:
> > > > >>>
> > > > >>> On Thu, Mar 16, 2023 at 02:26:18PM -0700, Namhyung Kim wrote:
> > > > >>>> Hello,
> > > > >>>>
> > > > >>>> On Thu, Mar 16, 2023 at 6:36 AM Artem Savkov <asavkov@redhat.com> wrote:
> > > > >>>>>
> > > > >>>>> In an email to Arnaldo Andrii Nakryiko suggested that perf can get
> > > > >>>>> information about inlined functions from dwarf when available and then
> > > > >>>>> add it to userspace stacktraces even in framepointer or lbr mode.
> > > > >>>>> Looking closer at perf it turned out all required bits and pieces are
> > > > >>>>> already there and inline information can be easily added to both
> > > > >>>>> framepointer and lbr callchains by adding an append_inlines() call to
> > > > >>>>> add_callchain_ip().
> > > > >>>>
> > > > >>>> Looks great! Have you checked it with perf report -g callee ?
> > > > >>>> I'm not sure the ordering of inlined functions is maintained
> > > > >>>> properly. Maybe you can use --no-children too to simplify
> > > > >>>> the output.
> > > > >>>
> > > > >>> Thanks for the suggestion. I actually have another test program with
> > > > >>> functions being numbered rather than (creatively) named, so it might be
> > > > >>> easier to use it to figure out ordering. Here's the code:
> > > > >>
> > > > >> Yep, looks good.
> > > > >>
> > > > >> Acked-by: Namhyung Kim <namhyung@kernel.org>
> > > > >
> > > > > So, I'll apply this shorter patch instead, ok?
> > > > >
> > > > > - Arnaldo
> > > > >
> > > > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> > > > > index 803c9d1803dd26ef..abf6167f28217fe6 100644
> > > > > --- a/tools/perf/util/machine.c
> > > > > +++ b/tools/perf/util/machine.c
> > > > > @@ -44,6 +44,7 @@
> > > > > #include <linux/zalloc.h>
> > > > >
> > > > > static void __machine__remove_thread(struct machine *machine, struct thread *th, bool lock);
> > > > > +static int append_inlines(struct callchain_cursor *cursor, struct map_symbol *ms, u64 ip);
> > > > >
> > > > > static struct dso *machine__kernel_dso(struct machine *machine)
> > > > > {
> > > > > @@ -2322,6 +2323,10 @@ static int add_callchain_ip(struct thread *thread,
> > > > > ms.maps = al.maps;
> > > > > ms.map = al.map;
> > > > > ms.sym = al.sym;
> > > > > +
> > > > > + if (append_inlines(cursor, &ms, ip) == 0)
> > > > > + return 0;
> > > > > +
> > > > > srcline = callchain_srcline(&ms, al.addr);
> > > > > return callchain_cursor_append(cursor, ip, &ms,
> > > > > branch, flags, nr_loop_iter,
> > > >
> > > > This seems to be breaking --branch-history. I am not sure
> > > > append_inlines() makes sense for branches. Maybe this should be:
> > > >
> > > > if (!branch && !append_inlines(cursor, &ms, ip))
> > > > return 0;
> > > >
> > >
> > > Right. So when cllchain_cursor is appended through append_inlines it
> > > always discards branch information, even for the non-inlined function.
> > > So adding !branch makes sense to me. Does anyone else see any problems
> > > with that?
> >
> > I'm no expert in this specific area, so for now till we get to a
> > conclusion on this, I'll follow Andi's suggestion and revert this patch.
>
> I think we can simply apply Adrian's patch above.
I can send a v2 with this fix included if that'll be more convenient.
--
Artem
next prev parent reply other threads:[~2023-04-04 6:59 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-16 13:35 [PATCH 0/1] perf report: append inlines to non-dwarf callchains Artem Savkov
2023-03-16 13:35 ` [PATCH 1/1] " Artem Savkov
2023-03-16 21:26 ` [PATCH 0/1] " Namhyung Kim
2023-03-17 7:41 ` Artem Savkov
2023-03-22 18:18 ` Namhyung Kim
2023-03-22 19:44 ` Arnaldo Carvalho de Melo
2023-03-23 8:22 ` Artem Savkov
2023-03-30 5:06 ` Adrian Hunter
2023-03-31 8:52 ` Artem Savkov
2023-04-03 20:30 ` Arnaldo Carvalho de Melo
2023-04-04 5:47 ` Namhyung Kim
2023-04-04 6:57 ` Adrian Hunter
2023-04-04 6:58 ` Artem Savkov [this message]
2023-04-04 12:22 ` Arnaldo Carvalho de Melo
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