perf record: Use sw counter only if hw pmu is not detected

Use cpu-clock-tick sw counter for cpu-cycles only if there is no hw
pmu available. This is the case if the syscall reports ENOENT. In
other cases (e.g. invalid attributes) we don't want the sw counter to
be used.

Cc: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/1333643188-26895-5-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Robert Richter 2012-04-05 18:26:28 +02:00 committed by Arnaldo Carvalho de Melo
parent 61d5bf5b01
commit 5a7ed29c75

View file

@ -245,7 +245,7 @@ static void perf_record__open(struct perf_record *rec)
* based cpu-clock-tick sw counter, which
* is always available even if no PMU support:
*/
if (attr->type == PERF_TYPE_HARDWARE
if (err == ENOENT && attr->type == PERF_TYPE_HARDWARE
&& attr->config == PERF_COUNT_HW_CPU_CYCLES) {
if (verbose)