From 18ffdfe8e98f861a39590ef2374ad51fc963567e Mon Sep 17 00:00:00 2001 From: Jiri Olsa <jolsa@kernel.org> Date: Mon, 25 May 2015 22:51:54 +0200 Subject: [PATCH] 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> --- tools/perf/util/evsel.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) 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", -- 2.20.1