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perf tools: Fix synthesizing fork_event.ppid for non-main thread

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Commit ca6c41c59b9 sets the ppid based on what is read from the
/proc/pid/status file when synthesizing fork events.

This is correct thing to do for new processes but not threads of a
process.

Fix ppid for threads to be the main thread when synthesizing fork events
(ie., assume main thread spawned all sub-threads in a process).

Reported-by: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Signed-off-by: David Ahern <david.ahern@oracle.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/1428598107-178999-1-git-send-email-david.ahern@oracle.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
David Ahern 2015-04-09 12:48:27 -04:00 committed by Arnaldo Carvalho de Melo
parent 51ab7155c0
commit 7764a385f6
1 changed files with 12 additions and 2 deletions
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14
tools/perf/util/event.c
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@ -183,8 +183,18 @@ static int perf_event__synthesize_fork(struct perf_tool *tool,
{
memset(&event->fork, 0, sizeof(event->fork) + machine->id_hdr_size);
event->fork.ppid = ppid;
event->fork.ptid = ppid;
/*
* for main thread set parent to ppid from status file. For other
* threads set parent pid to main thread. ie., assume main thread
* spawns all threads in a process
*/
if (tgid == pid) {
event->fork.ppid = ppid;
event->fork.ptid = ppid;
} else {
event->fork.ppid = tgid;
event->fork.ptid = tgid;
}
event->fork.pid = tgid;
event->fork.tid = pid;
event->fork.header.type = PERF_RECORD_FORK;