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s390/perf: Improve PMU selection for PERF_COUNT_HW_CPU_CYCLES events 

The cpum_cf (counter facility) PMU does not support sampling events.
With cpum_sf (sampling facility), a PMU for sampling CPU cycles is
available.

Make cpum_sf the "default" PMU for PERF_COUNT_HW_CPU_CYCLES sampling
events but use the more precise cpum_cf PMU for non-sampling events.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Hendrik Brueckner 2013-12-12 16:47:00 +01:00 committed by Martin Schwidefsky
parent 8c069ff4bd
commit 55baa2f831
1 changed files with 21 additions and 3 deletions
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24
arch/s390/kernel/perf_cpum_sf.c
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@ -468,11 +468,29 @@ static int cpumsf_pmu_event_init(struct perf_event *event)
{
int err;
if (event->attr.type != PERF_TYPE_RAW)
return -ENOENT;
/* No support for taken branch sampling */
if (has_branch_stack(event))
return -EOPNOTSUPP;
if (event->attr.config != PERF_EVENT_CPUM_SF)
switch (event->attr.type) {
case PERF_TYPE_RAW:
if (event->attr.config != PERF_EVENT_CPUM_SF)
return -ENOENT;
break;
case PERF_TYPE_HARDWARE:
/* Support sampling of CPU cycles in addition to the
* counter facility. However, the counter facility
* is more precise and, hence, restrict this PMU to
* sampling events only.
*/
if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES)
return -ENOENT;
if (!is_sampling_event(event))
return -ENOENT;
break;
default:
return -ENOENT;
}
if (event->cpu >= nr_cpumask_bits ||
(event->cpu >= 0 && !cpu_online(event->cpu)))