perf/arm-cci: Remove unnecessary period adjustment

Since sampling events are rejected up-front by cci_pmu_event_init(), it
doesn't make much sense to go fiddling with the sampling period later.
This would seem to be just another leftover artefact of the arm_pmu
framwork, and as such can go.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c
index 383b2d3..72c4644 100644 (file)
--- a/drivers/perf/arm-cci.c
+++ b/drivers/perf/arm-cci.c
@@ -1304,15 +1304,6 @@ static int __hw_perf_event_init(struct perf_event *event)
         */
        hwc->config_base            |= (unsigned long)mapping;
 
-       /*
-        * Limit the sample_period to half of the counter width. That way, the
-        * new counter value is far less likely to overtake the previous one
-        * unless you have some serious IRQ latency issues.
-        */
-       hwc->sample_period  = CCI_PMU_CNTR_MASK >> 1;
-       hwc->last_period    = hwc->sample_period;
-       local64_set(&hwc->period_left, hwc->sample_period);
-
        if (event->group_leader != event) {
                if (validate_group(event) != 0)
                        return -EINVAL;