Messages in this thread Patch in this message | | | Date | Fri, 27 Mar 2015 14:10:54 -0600 | From | David Ahern <> | Subject | Re: [PATCH v2] perf tool: Fix ppid for synthesized fork events |
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On 3/27/15 1:49 PM, Don Zickus wrote: > diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c > index 1c8fbc9..7ee3823 100644 > --- a/tools/perf/util/thread.c > +++ b/tools/perf/util/thread.c > @@ -187,6 +187,7 @@ static int thread__clone_map_groups(struct thread *thread, > if (thread->pid_ == parent->pid_) > return 0;
There's your answer ... the 2 lines above.
> > + printf("DON:\n"); > /* But this one is new process, copy maps. */ > for (i = 0; i < MAP__NR_TYPES; ++i) > if (map_groups__clone(thread->mg, parent->mg, i) < 0) > > before David's patch, we do _not_ see any DON markers. After David's patch > we see a 1:1 match of DON markers to the number of threads currently running > in the system.
Your "speed up" is based on the assumption that all synthesized threads are their own parent which is wrong. ie., ppid != tgid of the process.
Before ppid was getting initialized to -1. If you just make that change to revert to the -1:
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index d5efa5092ce6..ce4ca061c2e5 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -150,8 +150,8 @@ static int perf_event__synthesize_fork(struct perf_tool *tool, { memset(&event->fork, 0, sizeof(event->fork) + machine->id_hdr_size);
- event->fork.ppid = tgid; - event->fork.ptid = tgid; + event->fork.ppid = -1; + event->fork.ptid = -1; event->fork.pid = tgid; event->fork.tid = pid; event->fork.header.type = PERF_RECORD_FORK; You see the "DON" messages.
David
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