Re: [PATCH 2/5] perf record: Add error message for EMFILE

[Namhyung Kim]

Hello,

2012-01-30 12:28 AM, David Ahern wrote:
> On 01/29/2012 01:55 AM, Namhyung Kim wrote:
> > When a user tries to open so many events, perf_event_oen syscall
> > may fail with EMFILE. Provide an advice for that case.
> >
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxx>
> > ---
> >   tools/perf/builtin-record.c |    4 ++++
> >   1 files changed, 4 insertions(+), 0 deletions(-)
> >
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index 32870eef952f..5d3b6794d93b 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -249,6 +249,10 @@ try_again:
> >   				ui__warning("The %s event is not supported.\n",
> >   					    event_name(pos));
> >   				exit(EXIT_FAILURE);
> > +			} else if (err == EMFILE) {
> > +				ui__warning("Too many events are opened.\n"
> > +					    "Try again after reducing the number of events.\n");
> > +				exit(EXIT_FAILURE);
> >   			}
> >
> >   			printf("\n");
>
> It's not just the number of events: an fd is opened for each specified
> event on each specified cpu and for each specified task. See
> __perf_evsel__open(). e.g., the new --uid option on a 16 cpu server can
> hit the limit pretty fast.
>
> David

Right. How about this then? If it looks OK to you, I'll resend the patch 
for record, top, stat:

	Too many events are opened.
	Try again after reducing the number of events,
	tasks and/or cpus.


Thanks,
Namhyung
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