[PATCH 3/8] perf top: Add error message for EMFILE

[Namhyung Kim]

When a user tries to open so many events, perf_event_open syscall
may fail with EMFILE. Provide advise for that case.

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxx>
---
 tools/perf/builtin-top.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 4f81eeb99875..ad18dd37e87d 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -889,6 +889,10 @@ try_again:
 				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 "
-- 
1.7.6

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