Commit 7764a385 authored Apr 09, 2015 by David Ahern Committed by Arnaldo Carvalho de Melo Apr 10, 2015

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



Commit ca6c41c5 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>

parent 51ab7155

tools/perf/util/event.c

+12 −2

Original line number	Diff line number	Diff line
		@@ -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);

		/*
		* 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;