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>

1 files changed, 13 insertions, 11 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 027c4d33b4d..98c5549c8e2 100644
--- 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)