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authorArnaldo Carvalho de Melo <acme@redhat.com>2017-02-13 16:45:24 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-02-13 17:22:33 -0300
commitd6195a6a2c247515d5832debb51c03a74dc3f8f6 (patch)
tree18a5f7ae1648ab4167c8f2db7fd372b031bce600 /tools/perf/util
parente8c6f437fd12d39e462962eaed2315bac597d34c (diff)
perf evsel: Inform how to make a sysctl setting permanent
When a tool can't open counters due to the kernel.perf_event_paranoit sysctl setting, we inform how to tweak it to allow the operation to succeed, in addition to that, suggest setting /etc/sysctl.conf to make the setting permanent. Suggested-by: Ingo Molnar <mingo@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-4gwe99k4a6p12d4u8bbyttj2@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util')
-rw-r--r--tools/perf/util/evsel.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 04e536ae4d88..cd2fb42e5dd4 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2469,7 +2469,9 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
" -1: Allow use of (almost) all events by all users\n"
">= 0: Disallow raw tracepoint access by users without CAP_IOC_LOCK\n"
">= 1: Disallow CPU event access by users without CAP_SYS_ADMIN\n"
- ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN",
+ ">= 2: Disallow kernel profiling by users without CAP_SYS_ADMIN\n\n"
+ "To make this setting permanent, edit /etc/sysctl.conf too, e.g.:\n\n"
+ " kernel.perf_event_paranoid = -1\n" ,
target->system_wide ? "system-wide " : "",
perf_event_paranoid());
case ENOENT: