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

Arnaldo Carvalho de Melo
2016-06-03T14:39:58Z

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@huawei.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;
> > + }
> > }
> > }
>