Commits
Vince Weaver committed 88fee52e58c
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>