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authorArnaldo Carvalho de Melo <acme@redhat.com>2011-02-10 12:52:47 -0200
committerArnaldo Carvalho de Melo <acme@redhat.com>2011-02-10 12:52:47 -0200
commit401b8e1317d288f28d6e1afd13271dcb08fd9869 (patch)
tree8a6e8215cc54d27c2d03cb66ca6810c76240653d /tools
parent5651f7f47dbb1cf2b95a60582546db4ff508e2b4 (diff)
downloadlinux-2.6.38-lt-ux500-401b8e1317d288f28d6e1afd13271dcb08fd9869.tar.gz
perf tools: Fix thread_map event synthesizing in top and record
Jeff Moyer reported these messages: Warning: ... trying to fall back to cpu-clock-ticks couldn't open /proc/-1/status couldn't open /proc/-1/maps [ls output] [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.008 MB perf.data (~363 samples) ] That lead me and David Ahern to see that something was fishy on the thread synthesizing routines, at least for the case where the workload is started from 'perf record', as -1 is the default for target_tid in 'perf record --tid' parameter, so somehow we were trying to synthesize the PERF_RECORD_MMAP and PERF_RECORD_COMM events for the thread -1, a bug. So I investigated this and noticed that when we introduced support for recording a process and its threads using --pid some bugs were introduced and that the way to fix it was to instead of passing the target_tid to the event synthesizing routines we should better pass the thread_map that has the list of threads for a --pid or just the single thread for a --tid. Checked in the following ways: On a 8-way machine run cyclictest: [root@emilia ~]# perf record cyclictest -a -t -n -p99 -i100 -d50 policy: fifo: loadavg: 0.00 0.13 0.31 2/139 28798 T: 0 (28791) P:99 I:100 C: 25072 Min: 4 Act: 5 Avg: 6 Max: 122 T: 1 (28792) P:98 I:150 C: 16715 Min: 4 Act: 6 Avg: 5 Max: 27 T: 2 (28793) P:97 I:200 C: 12534 Min: 4 Act: 5 Avg: 4 Max: 8 T: 3 (28794) P:96 I:250 C: 10028 Min: 4 Act: 5 Avg: 5 Max: 96 T: 4 (28795) P:95 I:300 C: 8357 Min: 5 Act: 6 Avg: 5 Max: 12 T: 5 (28796) P:94 I:350 C: 7163 Min: 5 Act: 6 Avg: 5 Max: 12 T: 6 (28797) P:93 I:400 C: 6267 Min: 4 Act: 5 Avg: 5 Max: 9 T: 7 (28798) P:92 I:450 C: 5571 Min: 4 Act: 5 Avg: 5 Max: 9 ^C[ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.108 MB perf.data (~4719 samples) ] [root@emilia ~]# This will create one extra thread per CPU: [root@emilia ~]# tuna -t cyclictest -CP thread ctxt_switches pid SCHED_ rtpri affinity voluntary nonvoluntary cmd 28825 OTHER 0 0xff 2169 671 cyclictest 28832 FIFO 93 6 52338 1 cyclictest 28833 FIFO 92 7 46524 1 cyclictest 28826 FIFO 99 0 209360 1 cyclictest 28827 FIFO 98 1 139577 1 cyclictest 28828 FIFO 97 2 104686 0 cyclictest 28829 FIFO 96 3 83751 1 cyclictest 28830 FIFO 95 4 69794 1 cyclictest 28831 FIFO 94 5 59825 1 cyclictest [root@emilia ~]# So we should expect only samples for the above 9 threads when using the --dump-raw-trace|-D perf report switch to look at the column with the tid: [root@emilia ~]# perf report -D | grep RECORD_SAMPLE | cut -d/ -f2 | cut -d: -f1 | sort | uniq -c 629 28825 110 28826 491 28827 308 28828 198 28829 621 28830 225 28831 203 28832 89 28833 [root@emilia ~]# So for workloads started by 'perf record' seems to work, now for existing workloads, just run cyclictest first, without 'perf record': [root@emilia ~]# tuna -t cyclictest -CP thread ctxt_switches pid SCHED_ rtpri affinity voluntary nonvoluntary cmd 28859 OTHER 0 0xff 594 200 cyclictest 28864 FIFO 95 4 16587 1 cyclictest 28865 FIFO 94 5 14219 1 cyclictest 28866 FIFO 93 6 12443 0 cyclictest 28867 FIFO 92 7 11062 1 cyclictest 28860 FIFO 99 0 49779 1 cyclictest 28861 FIFO 98 1 33190 1 cyclictest 28862 FIFO 97 2 24895 1 cyclictest 28863 FIFO 96 3 19918 1 cyclictest [root@emilia ~]# and then later did: [root@emilia ~]# perf record --pid 28859 sleep 3 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.027 MB perf.data (~1195 samples) ] [root@emilia ~]# To collect 3 seconds worth of samples for pid 28859 and its children: [root@emilia ~]# perf report -D | grep RECORD_SAMPLE | cut -d/ -f2 | cut -d: -f1 | sort | uniq -c 15 28859 33 28860 19 28861 13 28862 13 28863 10 28864 11 28865 9 28866 255 28867 [root@emilia ~]# Works, last thing is to check if looking at just one of those threads also works: [root@emilia ~]# perf record --tid 28866 sleep 3 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.006 MB perf.data (~242 samples) ] [root@emilia ~]# perf report -D | grep RECORD_SAMPLE | cut -d/ -f2 | cut -d: -f1 | sort | uniq -c 3 28866 [root@emilia ~]# Works too. Reported-by: Jeff Moyer <jmoyer@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/builtin-record.c4
-rw-r--r--tools/perf/builtin-top.c2
-rw-r--r--tools/perf/util/event.c18
-rw-r--r--tools/perf/util/event.h6
4 files changed, 20 insertions, 10 deletions
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index b2f729fdb31..60cac6f92e8 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -759,8 +759,8 @@ static int __cmd_record(int argc, const char **argv)
perf_session__process_machines(session, event__synthesize_guest_os);
if (!system_wide)
- event__synthesize_thread(target_tid, process_synthesized_event,
- session);
+ event__synthesize_thread_map(threads, process_synthesized_event,
+ session);
else
event__synthesize_threads(process_synthesized_event, session);
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index b6998e05576..5a29d9cd948 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1306,7 +1306,7 @@ static int __cmd_top(void)
return -ENOMEM;
if (target_tid != -1)
- event__synthesize_thread(target_tid, event__process, session);
+ event__synthesize_thread_map(threads, event__process, session);
else
event__synthesize_threads(event__process, session);
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 1478ab4ee22..50d0a931497 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -263,11 +263,12 @@ static int __event__synthesize_thread(event_t *comm_event, event_t *mmap_event,
process, session);
}
-int event__synthesize_thread(pid_t pid, event__handler_t process,
- struct perf_session *session)
+int event__synthesize_thread_map(struct thread_map *threads,
+ event__handler_t process,
+ struct perf_session *session)
{
event_t *comm_event, *mmap_event;
- int err = -1;
+ int err = -1, thread;
comm_event = malloc(sizeof(comm_event->comm) + session->id_hdr_size);
if (comm_event == NULL)
@@ -277,8 +278,15 @@ int event__synthesize_thread(pid_t pid, event__handler_t process,
if (mmap_event == NULL)
goto out_free_comm;
- err = __event__synthesize_thread(comm_event, mmap_event, pid,
- process, session);
+ err = 0;
+ for (thread = 0; thread < threads->nr; ++thread) {
+ if (__event__synthesize_thread(comm_event, mmap_event,
+ threads->map[thread],
+ process, session)) {
+ err = -1;
+ break;
+ }
+ }
free(mmap_event);
out_free_comm:
free(comm_event);
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 2b7e91902f1..cc7b52f9b49 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -135,14 +135,16 @@ typedef union event_union {
void event__print_totals(void);
struct perf_session;
+struct thread_map;
typedef int (*event__handler_synth_t)(event_t *event,
struct perf_session *session);
typedef int (*event__handler_t)(event_t *event, struct sample_data *sample,
struct perf_session *session);
-int event__synthesize_thread(pid_t pid, event__handler_t process,
- struct perf_session *session);
+int event__synthesize_thread_map(struct thread_map *threads,
+ event__handler_t process,
+ struct perf_session *session);
int event__synthesize_threads(event__handler_t process,
struct perf_session *session);
int event__synthesize_kernel_mmap(event__handler_t process,