perf top: Add error message for EMFILE

When a user tries to open so many events, perf_event_open syscall may fail with EMFILE. Provide advise for that case. Cc: Ingo Molnar <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Namhyung Kim <[email protected]> Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
kerow · Jan 8, 2012 · cdce445 · cdce445
1 parent c30ab8a
commit cdce445
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
@@ -888,6 +888,10 @@ static void perf_top__start_counters(struct perf_top *top)
 				ui__warning("The %s event is not supported.\n",
 					    event_name(counter));
 				goto out_err;
+			} else if (err == EMFILE) {
+				ui__warning("Too many events are opened.\n"
+					    "Try again after reducing the number of events\n");
+				goto out_err;
 			}
 
 			ui__warning("The sys_perf_event_open() syscall "