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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-05-20 12:21:21 +0200
committerIngo Molnar <mingo@elte.hu>2009-05-20 12:43:33 +0200
commitb986d7ec0f8b7ea3cc7366d80a137fbe839df227 (patch)
treead3e9c473b8790f800cbf9e13e3fee01230def52 /kernel/perf_counter.c
parentperf_counter: Log irq_period changes (diff)
downloadlinux-dev-b986d7ec0f8b7ea3cc7366d80a137fbe839df227.tar.xz
linux-dev-b986d7ec0f8b7ea3cc7366d80a137fbe839df227.zip
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>
Diffstat (limited to 'kernel/perf_counter.c')
-rw-r--r--kernel/perf_counter.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index db02eb16c777..473ed2cafbfc 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -2716,7 +2716,8 @@ static int cpu_clock_perf_counter_enable(struct perf_counter *counter)
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 int task_clock_perf_counter_enable(struct perf_counter *counter)
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);
}