On Wed, May 20, 2015 at 11:48:35AM +0900, Namhyung Kim wrote: > When perf creates a new child to profile, the events are enabled on > exec(). And in this case, it doesn't synthesize any event for the > child since they'll be generated during exec(). But there's an window > between the enabling and the event generation. > > It used to be overcome since samples are only in kernel (so we always > have the map) and the comm is overridden by a later COMM event. > However it won't work if events are processed and displayed before the > COMM event overrides like in 'perf script'. This leads to those early > samples (like native_write_msr_safe) not having a comm but pid (like > ':15328'). > > So it needs to synthesize COMM event for the child explicitly before > enabling so that it can have a correct comm. But at this time, the > comm will be "perf" since it's not exec-ed yet. > > Signed-off-by: Namhyung Kim <[email protected]> > --- > tools/perf/builtin-record.c | 41 ++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 40 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 5dfe91395617..a0821ee92e27 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -469,6 +469,43 @@ static void workload_exec_failed_signal(int signo > __maybe_unused, > child_finished = 1; > } > > +static int synthesize_workload_comm_event(struct perf_evlist *evlist, void > *arg) > +{ > + union perf_event *event; > + struct record *rec = arg; > + struct machine *machine = &rec->session->machines.host; > + int pid = evlist->workload.pid; > + const char *comm_str = program_invocation_short_name;
never heard of program_invocation_short_name ;-) nice.. for the patchset: Acked-by: Jiri Olsa <[email protected]> I tested the record/script use case.. works ok thanks, jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
