From: Jiri Olsa <jolsa@kernel.org>
Date: Mon, 25 May 2015 20:51:54 +0000 (+0200)
Subject: perf tools: Add hint for 'Too many events are opened.' error message
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=18ffdfe8e98f861a39590ef2374ad51fc963567e;p=linux-beck.git

perf tools: Add hint for 'Too many events are opened.' error message

Enhancing the 'Too many events are opened.' error message with hint to
use use 'ulimit -n <limit>' command.

Before:

  $ perf record -e 'sched:*,syscalls:*' ls
  Error:
  Too many events are opened.
  Try again after reducing the number of events.

Now:

  $ perf record -e 'sched:*,syscalls:*' ls
  Error:
  Too many events are opened.
  Probably the maximum number of open file descriptors has been reached.
  Hint: Try again after reducing the number of events.
  Hint: Try increasing the limit with 'ulimit -n <limit>'

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1432587114-14924-1-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index c886b9f7a48d..a3e36fc634dc 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2149,7 +2149,9 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
 	case EMFILE:
 		return scnprintf(msg, size, "%s",
 			 "Too many events are opened.\n"
-			 "Try again after reducing the number of events.");
+			 "Probably the maximum number of open file descriptors has been reached.\n"
+			 "Hint: Try again after reducing the number of events.\n"
+			 "Hint: Try increasing the limit with 'ulimit -n <limit>'");
 	case ENODEV:
 		if (target->cpu_list)
 			return scnprintf(msg, size, "%s",