From 8614ada0be7d7be84b85c006d526a9c8f76484fa Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 6 Feb 2018 19:17:57 +0100 Subject: [PATCH] perf report: Ask for ordered events for --tasks option If we have the time in, keep the events in time order. Committer notes: Trying to be more verbose, what actual effect this will have in this particular case? Before and after this patch shows the artifacts: --- /tmp/before 2018-02-06 15:40:29.536411625 -0300 +++ /tmp/after 2018-02-06 15:40:51.963403599 -0300 @@ -5,34 +5,34 @@ 2540 2540 1818 | gnome-terminal- 3489 3489 2540 | bash 32433 32433 3489 | perf - 32434 32434 32433 | perf + 32434 32434 32433 | make 32441 32441 32434 | make 32514 32514 32441 | make 511 511 32514 | sh - 512 512 511 | sh + 512 512 511 | install We don't have 'perf' calling 'perf' calling 'make', etc, the second 'perf' actually is 'make', i.e. there was reordering of the relevant PERF_RECORD_COMM and PERF_RECORD_FORK records. Ditto for sh/install later on. Look for FORK and COMM meta events, for those tids: # perf report -D | egrep 'PERF_RECORD_(FORK|COMM)' | egrep '3243[34]' 0 14774650990679 0x1a3cd8 [0x38]: PERF_RECORD_FORK(32433:32433):(3489:3489) 1 14774652080381 0x1d6568 [0x30]: PERF_RECORD_COMM exec: perf:32433/32433 1 14774742473340 0x1dbb48 [0x38]: PERF_RECORD_FORK(32434:32434):(32433:32433) 0 14774752005779 0x1a4af8 [0x30]: PERF_RECORD_COMM exec: make:32434/32434 0 14774753997960 0x1a5578 [0x38]: PERF_RECORD_FORK(32435:32435):(32434:32434) 0 14774756070782 0x1a5618 [0x38]: PERF_RECORD_FORK(32438:32438):(32434:32434) 0 14774757772939 0x1a5680 [0x38]: PERF_RECORD_FORK(32440:32440):(32434:32434) 0 14774758230600 0x1a56e8 [0x38]: PERF_RECORD_FORK(32441:32441):(32434:32434) # First column is the cpu, second is the timestamp. So they are on different CPUs, thus ring buffers, and when we don't use the ordered_events class, we end up mixing that up, use it to take advantage of the PERF_RECORD_FINISHED_ROUND meta events to go on ordering the events using the PERF_SAMPLE_TIME present in the PERF_RECORD_{FORK,COMM,EXIT,SAMPLE,etc} records in the ring buffer. Signed-off-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20180206181813.10943-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-report.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c index 4ad5dc649716..8ef71669e7a0 100644 --- a/tools/perf/builtin-report.c +++ b/tools/perf/builtin-report.c @@ -614,6 +614,7 @@ static int stats_print(struct report *rep) static void tasks_setup(struct report *rep) { memset(&rep->tool, 0, sizeof(rep->tool)); + rep->tool.ordered_events = true; if (rep->mmaps_mode) { rep->tool.mmap = perf_event__process_mmap; rep->tool.mmap2 = perf_event__process_mmap2;