Messages in this thread | | | Date | Mon, 3 Apr 2023 17:30:17 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH 0/1] perf report: append inlines to non-dwarf callchains |
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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.
- Arnaldo
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