From: Arnaldo Carvalho de Melo <a...@redhat.com> 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 <mi...@kernel.org> Cc: Adrian Hunter <adrian.hun...@intel.com> Cc: David Ahern <dsah...@gmail.com> Cc: Jiri Olsa <jo...@kernel.org> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Wang Nan <wangn...@huawei.com> Link: http://lkml.kernel.org/n/tip-4gwe99k4a6p12d4u8bbyt...@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/builtin-record.c | 2 +- tools/perf/builtin-stat.c | 2 +- tools/perf/builtin-top.c | 2 +- tools/perf/util/evsel.c | 4 +++- 4 files changed, 6 insertions(+), 4 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index ffac8ca9fb01..2ddf189968dc 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -418,7 +418,7 @@ static int record__mmap(struct record *rec) static int record__open(struct record *rec) { - char msg[512]; + char msg[BUFSIZ]; struct perf_evsel *pos; struct perf_evlist *evlist = rec->evlist; struct perf_session *session = rec->session; diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index a02f2e965628..f28719178b51 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -533,7 +533,7 @@ static int store_counter_ids(struct perf_evsel *counter) static int __run_perf_stat(int argc, const char **argv) { int interval = stat_config.interval; - char msg[512]; + char msg[BUFSIZ]; unsigned long long t0, t1; struct perf_evsel *counter; struct timespec ts; diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index d90927f31ff6..5a7fd7af3a6d 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -859,7 +859,7 @@ static void perf_top__mmap_read(struct perf_top *top) static int perf_top__start_counters(struct perf_top *top) { - char msg[512]; + char msg[BUFSIZ]; struct perf_evsel *counter; struct perf_evlist *evlist = top->evlist; struct record_opts *opts = &top->record_opts; 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: -- 2.9.3
