perf_counter: Optimize disable of time based sw counters
Currently we call hrtimer_cancel() unconditionally on disable of time based
software counters. Avoid when possible.
[ Impact: micro-optimize the code ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
LKML-Reference: <20090520102553.388185031@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index db02eb1..473ed2c 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2716,7 +2716,8 @@
static void cpu_clock_perf_counter_disable(struct perf_counter *counter)
{
- hrtimer_cancel(&counter->hw.hrtimer);
+ if (counter->hw.irq_period)
+ hrtimer_cancel(&counter->hw.hrtimer);
cpu_clock_perf_counter_update(counter);
}
@@ -2767,7 +2768,8 @@
static void task_clock_perf_counter_disable(struct perf_counter *counter)
{
- hrtimer_cancel(&counter->hw.hrtimer);
+ if (counter->hw.irq_period)
+ hrtimer_cancel(&counter->hw.hrtimer);
task_clock_perf_counter_update(counter, counter->ctx->time);
}