From: David Ahern Date: Thu, 9 Apr 2015 16:48:27 +0000 (-0400) Subject: perf tools: Fix synthesizing fork_event.ppid for non-main thread X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7764a385f60bd200304a33124bdb4e684caeabdf;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git perf tools: Fix synthesizing fork_event.ppid for non-main thread 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 Signed-off-by: David Ahern Tested-by: Arnaldo Carvalho de Melo Acked-by: Don Zickus Link: http://lkml.kernel.org/r/1428598107-178999-1-git-send-email-david.ahern@oracle.com Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 5516236df6ab..9d0985131252 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -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;