perf: Don't bother to init the hrtimer for no SW sampling counters

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1290525705-6265-3-git-send-email-fbuihuu@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 027c4d3..98c5549 100644 (file)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4917,24 +4917,26 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 static void perf_swevent_start_hrtimer(struct perf_event *event)
 {
        struct hw_perf_event *hwc = &event->hw;
+       s64 period;
+
+       if (!is_sampling_event(event))
+               return;
 
        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        hwc->hrtimer.function = perf_swevent_hrtimer;
-       if (is_sampling_event(event)) {
-               s64 period = local64_read(&hwc->period_left);
 
-               if (period) {
-                       if (period < 0)
-                               period = 10000;
+       period = local64_read(&hwc->period_left);
+       if (period) {
+               if (period < 0)
+                       period = 10000;
 
-                       local64_set(&hwc->period_left, 0);
-               } else {
-                       period = max_t(u64, 10000, hwc->sample_period);
-               }
-               __hrtimer_start_range_ns(&hwc->hrtimer,
+               local64_set(&hwc->period_left, 0);
+       } else {
+               period = max_t(u64, 10000, hwc->sample_period);
+       }
+       __hrtimer_start_range_ns(&hwc->hrtimer,
                                ns_to_ktime(period), 0,
                                HRTIMER_MODE_REL_PINNED, 0);
-       }
 }
 
 static void perf_swevent_cancel_hrtimer(struct perf_event *event)