[tip:perf/core] perf script: Show call graphs when 1st event doesn't have it but some other has

tip-bot for He Kuang
2016-06-08T08:38:53Z

Commit-ID: 40f20e5074b035c7111e135aa939d1d1a96a2480
Gitweb: http://git.kernel.org/tip/40f20e5074b035c7111e135aa939d1d1a96a2480
Author: He Kuang <hekuang@huawei.com>
AuthorDate: Mon, 16 May 2016 04:51:19 +0000
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 3 Jun 2016 14:53:46 -0300

perf script: Show call graphs when 1st event doesn't have it but some other has

There's a display inconsistency when there are multiple tracepoint
events, some of which have the 'call-graph' config option set but the
first one hasn't, i.e. the whole logic for call graph processing is
enabled only if the first tracepoint event has call-graph set.

For instance, if we record signal_deliver with call-graph and
signal_generate without:

$ 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 traverses 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>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1463374279-97209-1-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.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 e3ce2f3..4601123 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;
+ }
}
}