linux-kernel - Re: [PATCH 1/1] Revert "perf report: Append inlines to non-DWARF callchains"

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Date:   Mon, 7 Aug 2023 13:00:08 +0200
From:   Artem Savkov <asavkov@...hat.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Andrii Nakryiko <andrii.nakryiko@...il.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Ian Rogers <irogers@...gle.com>,
        Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Milian Wolff <milian.wolff@...b.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/1] Revert "perf report: Append inlines to non-DWARF
 callchains"

On Wed, Aug 02, 2023 at 09:43:40AM +0200, Artem Savkov wrote:
> Hi Arnaldo,
> 
> On Tue, Aug 01, 2023 at 06:42:47PM -0300, Arnaldo Carvalho de Melo wrote:
> > Hi Artem,
> > 
> > 	Can you please double check this? I reproduced with:
> > 
> > git checkout 46d21ec067490ab9cdcc89b9de5aae28786a8b8e
> > build it
> > perf record -a -g sleep 5s
> > perf report
> > 
> > 	Do you get the same slowness and then reverting it, i.e. just
> > going to HEAD~ and rebuilding getting a fast 'perf report' startup, i.e.
> > without the inlines in the callchains?
> 
> With a simple test like this I definitely get a slowdown, but not sure
> if it can be called excessive.
> 
> Below are the times I got by running 'time perf report' and hitting 'q'
> during load so that it quits as soon as it is loads up. Tested on a
> freshly updated fedora 38.

My bad, I had wrong debuginfo installed for the kernel I tested. I can
reproduce it with the correct one. Looks like vmlinux is just too much
for addr2line. Maybe we can skip it but leave other inlines in, like so:

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 11de3ca8d4fa7..fef309cd401f7 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2388,7 +2388,9 @@ static int add_callchain_ip(struct thread *thread,
 	ms.map = map__get(al.map);
 	ms.sym = al.sym;
 
-	if (!branch && append_inlines(cursor, &ms, ip) == 0)
+	if (!branch && ms.map && ms.map->dso &&
+	    strcmp(ms.map->dso->short_name, "[kernel.vmlinux]") &&
+	    append_inlines(cursor, &ms, ip) == 0)
 		goto out;
 
 	srcline = callchain_srcline(&ms, al.addr);

> > - Arnaldo
> > 
> > ----
> > 
> > This reverts commit 46d21ec067490ab9cdcc89b9de5aae28786a8b8e.
> > 
> > The tests were made with a specific workload, further tests on a
> > recently updated fedora 38 system with a system wide perf.data file
> > shows 'perf report' taking excessive time, so lets revert this until a
> > full investigation and improvement on the addr2line support code is
> > made.
> > 
> > Cc: Andrii Nakryiko <andrii.nakryiko@...il.com>
> > Cc: Artem Savkov <asavkov@...hat.com>
> > Cc: Namhyung Kim <namhyung@...nel.org>
> > Cc: Adrian Hunter <adrian.hunter@...el.com>
> > Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> > Cc: Ian Rogers <irogers@...gle.com>
> > Cc: Ingo Molnar <mingo@...hat.com>
> > Cc: Jiri Olsa <jolsa@...nel.org>
> > Cc: Mark Rutland <mark.rutland@....com>
> > Cc: Masami Hiramatsu <mhiramat@...nel.org>
> > Cc: Milian Wolff <milian.wolff@...b.com>
> > Cc: Peter Zijlstra <peterz@...radead.org>
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> > ---
> >  tools/perf/util/machine.c | 5 -----
> >  1 file changed, 5 deletions(-)
> > 
> > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> > index 4e62843d51b7dbf9..f4cb41ee23cdbcfc 100644
> > --- a/tools/perf/util/machine.c
> > +++ b/tools/perf/util/machine.c
> > @@ -45,7 +45,6 @@
> >  
> >  static void __machine__remove_thread(struct machine *machine, struct thread_rb_node *nd,
> >  				     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)
> >  {
> > @@ -2385,10 +2384,6 @@ static int add_callchain_ip(struct thread *thread,
> >  	ms.maps = maps__get(al.maps);
> >  	ms.map = map__get(al.map);
> >  	ms.sym = al.sym;
> > -
> > -	if (!branch && append_inlines(cursor, &ms, ip) == 0)
> > -		goto out;
> > -
> >  	srcline = callchain_srcline(&ms, al.addr);
> >  	err = callchain_cursor_append(cursor, ip, &ms,
> >  				      branch, flags, nr_loop_iter,
> > -- 
> > 2.41.0
> > 
> 
> -- 
>  Artem

-- 
 Artem