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