diff options
| author | Vince Weaver <vincent.weaver@maine.edu> | 2013-12-30 15:39:45 -0500 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-02-10 11:34:31 -0300 |
| commit | 88fee52e58ca14d8465b614774ed0bf08e1a7790 (patch) | |
| tree | d0043a4b7886fdfa76ed6bc0d95e24df2b03e079 /tools | |
| parent | f67697bd079f4bbcbe7d6d26765a06b18afe0630 (diff) | |
| download | linux-88fee52e58ca14d8465b614774ed0bf08e1a7790.tar.bz2 | |
perf list: Fix checking for supported events on older kernels
"perf list" listing of hardware events doesn't work on older ARM devices.
The change enabling event detection:
commit b41f1cec91c37eeea6fdb15effbfa24ea0a5536b
Author: Namhyung Kim <namhyung.kim@lge.com>
Date: Tue Aug 27 11:41:53 2013 +0900
perf list: Skip unsupported events
uses the following code in tools/perf/util/parse-events.c:
struct perf_event_attr attr = {
.type = type,
.config = config,
.disabled = 1,
.exclude_kernel = 1,
};
On ARM machines pre-dating the Cortex-A15 this doesn't work, as these
machines don't support .exclude_kernel. So starting with 3.12 "perf
list" does not report any hardware events at all on older machines (seen
on Rasp-Pi, Pandaboard, Beagleboard, etc).
This version of the patch makes changes suggested by Namhyung Kim to
check for EACCESS and retry (instead of just dropping the
exclude_kernel) so we can properly handle machines where
/proc/sys/kernel/perf_event_paranoid is set to 2.
Reported-by: Chad Paradis <chad.paradis@umit.maine.edu>
Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Chad Paradis <chad.paradis@umit.maine.edu>
Cc: Ingo Molnar <mingo@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/alpine.DEB.2.10.1312301536150.28814@vincent-weaver-1.um.maine.edu
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/util/parse-events.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index d248fca6d7ed..1e15df10a88c 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -1091,12 +1091,12 @@ int is_valid_tracepoint(const char *event_string) static bool is_event_supported(u8 type, unsigned config) { bool ret = true; + int open_return; struct perf_evsel *evsel; struct perf_event_attr attr = { .type = type, .config = config, .disabled = 1, - .exclude_kernel = 1, }; struct { struct thread_map map; @@ -1108,7 +1108,20 @@ static bool is_event_supported(u8 type, unsigned config) evsel = perf_evsel__new(&attr); if (evsel) { - ret = perf_evsel__open(evsel, NULL, &tmap.map) >= 0; + open_return = perf_evsel__open(evsel, NULL, &tmap.map); + ret = open_return >= 0; + + if (open_return == -EACCES) { + /* + * This happens if the paranoid value + * /proc/sys/kernel/perf_event_paranoid is set to 2 + * Re-run with exclude_kernel set; we don't do that + * by default as some ARM machines do not support it. + * + */ + evsel->attr.exclude_kernel = 1; + ret = perf_evsel__open(evsel, NULL, &tmap.map) >= 0; + } perf_evsel__delete(evsel); } |