linux-kernel - Re: [PATCH] perf script: Fix display inconsitency when call-graph config is used

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Date:	Fri, 3 Jun 2016 11:39:52 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	"Wangnan (F)" <wangnan0@...wei.com>
Cc:	alexander.shishkin@...ux.intel.com, dsahern@...il.com,
	He Kuang <hekuang@...wei.com>, peterz@...radead.org,
	mingo@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf script: Fix display inconsitency when call-graph
 config is used

Em Fri, Jun 03, 2016 at 04:38:04PM +0800, Wangnan (F) escreveu:
> Hi, Arnaldo and David,
> 
> Could you please have a look at this patch? It solves a perf script problem
> when
> dealing with mixed call-graph and no-call-graph events.

Sorry for the delay, I reproduced the problem and applied the patch,
thanks a lot!

- Arnaldo
 
> Thank you.
> 
> On 2016/5/16 12:51, He Kuang wrote:
> > There's a display inconsistency when 'call-graph' config event appears
> > in different position. The problem can be reproduced like this:
> > 
> > We record signal_deliver with call-graph and signal_generate without it.
> > 
> >    $ perf record -g -a -e signal:signal_deliver -e signal:signal_generate/call-graph=no/
> > 
> >    [ perf record: Captured and wrote 0.017 MB perf.data (2 samples) ]
> > 
> >    $ perf script
> > 
> >    kworker/u2:1    13 [000]  6563.875949: signal:signal_generate: sig=2 errno=0 code=128 comm=perf pid=1313 grp=1 res=0 ff61cc __send_signal+0x3ec ([kernel.kallsyms])
> >    perf  1313 [000]  6563.877584:  signal:signal_deliver: sig=2 errno=0 code=128 sa_handler=43115e sa_flags=14000000
> >                7ffff314 get_signal+0x80007f0023a4 ([kernel.kallsyms])
> >                7fffe358 do_signal+0x80007f002028 ([kernel.kallsyms])
> >                7fffa5e8 exit_to_usermode_loop+0x80007f002053 ([kernel.kallsyms])
> >                ...
> > 
> > Then we exchange the order of these two events in commandline, and keep
> > signal_generate without call-graph.
> > 
> >    $ perf record -g -a -e signal:signal_generate/call-graph=no/ -e signal:signal_deliver
> > 
> >    [ perf record: Captured and wrote 0.017 MB perf.data (2 samples) ]
> > 
> >    $ perf script
> > 
> >      kworker/u2:2  1314 [000]  6933.353060: signal:signal_generate: sig=2 errno=0 code=128 comm=perf pid=1321 grp=1 res=0
> >              perf  1321 [000]  6933.353872:  signal:signal_deliver: sig=2 errno=0 code=128 sa_handler=43115e sa_flags=14000000
> > 
> > This time, the callchain of the event signal_deliver disappeared. The
> > problem is caused by that perf only checks for the first evsel in evlist
> > and decides if callchain should be printed.
> > 
> > This patch travseres all evsels in evlist to see if any of them have
> > callchains, and shows the right result:
> > 
> >    $ perf script
> > 
> >    kworker/u2:2  1314 [000]  6933.353060: signal:signal_generate: sig=2 errno=0 code=128 comm=perf pid=1321 grp=1 res=0 ff61cc __send_signal+0x3ec ([kernel.kallsyms])
> >    perf  1321 [000]  6933.353872:  signal:signal_deliver: sig=2 errno=0 code=128 sa_handler=43115e sa_flags=14000000
> >                7ffff314 get_signal+0x80007f0023a4 ([kernel.kallsyms])
> >                7fffe358 do_signal+0x80007f002028 ([kernel.kallsyms])
> >                7fffa5e8 exit_to_usermode_loop+0x80007f002053 ([kernel.kallsyms])
> >                ...
> > 
> > Signed-off-by: He Kuang <hekuang@...wei.com>
> > ---
> >   tools/perf/builtin-script.c | 23 +++++++++++++----------
> >   1 file changed, 13 insertions(+), 10 deletions(-)
> > 
> > diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> > index efca816..7a18b92 100644
> > --- a/tools/perf/builtin-script.c
> > +++ b/tools/perf/builtin-script.c
> > @@ -339,7 +339,7 @@ static void set_print_ip_opts(struct perf_event_attr *attr)
> >    */
> >   static int perf_session__check_output_opt(struct perf_session *session)
> >   {
> > -	int j;
> > +	unsigned int j;
> >   	struct perf_evsel *evsel;
> >   	for (j = 0; j < PERF_TYPE_MAX; ++j) {
> > @@ -388,17 +388,20 @@ static int perf_session__check_output_opt(struct perf_session *session)
> >   		struct perf_event_attr *attr;
> >   		j = PERF_TYPE_TRACEPOINT;
> > -		evsel = perf_session__find_first_evtype(session, j);
> > -		if (evsel == NULL)
> > -			goto out;
> > -		attr = &evsel->attr;
> > +		evlist__for_each(session->evlist, evsel) {
> > +			if (evsel->attr.type != j)
> > +				continue;
> > +
> > +			attr = &evsel->attr;
> > -		if (attr->sample_type & PERF_SAMPLE_CALLCHAIN) {
> > -			output[j].fields |= PERF_OUTPUT_IP;
> > -			output[j].fields |= PERF_OUTPUT_SYM;
> > -			output[j].fields |= PERF_OUTPUT_DSO;
> > -			set_print_ip_opts(attr);
> > +			if (attr->sample_type & PERF_SAMPLE_CALLCHAIN) {
> > +				output[j].fields |= PERF_OUTPUT_IP;
> > +				output[j].fields |= PERF_OUTPUT_SYM;
> > +				output[j].fields |= PERF_OUTPUT_DSO;
> > +				set_print_ip_opts(attr);
> > +				goto out;
> > +			}
> >   		}
> >   	}
>