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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-06-22 13:58:35 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-23 11:42:46 +0200
commitf344011ccb85469445369153c3d27c4ee4bc2ac8 (patch)
tree66f041a826d09c690a5e6bb3d091494d52bc8565
parentb84fbc9fb1d943e2c5f4efe52ed0e3c93a4bdb6a (diff)
perf_counter: Optimize perf_counter_alloc()'s inherit case
We don't need to add usage counts for swcounter and attr usage models for inherited counters since the parent counter will always have one, which suffices to generate the needed output. This avoids up to 3 global atomic increments per inherited counter. LKML-Reference: <new-submission> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/perf_counter.c32
1 files changed, 20 insertions, 12 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 0a45490f402..c2b19c11171 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1508,11 +1508,13 @@ static void free_counter(struct perf_counter *counter)
{
perf_pending_sync(counter);
- atomic_dec(&nr_counters);
- if (counter->attr.mmap)
- atomic_dec(&nr_mmap_counters);
- if (counter->attr.comm)
- atomic_dec(&nr_comm_counters);
+ if (!counter->parent) {
+ atomic_dec(&nr_counters);
+ if (counter->attr.mmap)
+ atomic_dec(&nr_mmap_counters);
+ if (counter->attr.comm)
+ atomic_dec(&nr_comm_counters);
+ }
if (counter->destroy)
counter->destroy(counter);
@@ -3515,6 +3517,8 @@ static void sw_perf_counter_destroy(struct perf_counter *counter)
{
u64 event = counter->attr.config;
+ WARN_ON(counter->parent);
+
atomic_dec(&perf_swcounter_enabled[event]);
}
@@ -3551,8 +3555,10 @@ static const struct pmu *sw_perf_counter_init(struct perf_counter *counter)
case PERF_COUNT_SW_PAGE_FAULTS_MAJ:
case PERF_COUNT_SW_CONTEXT_SWITCHES:
case PERF_COUNT_SW_CPU_MIGRATIONS:
- atomic_inc(&perf_swcounter_enabled[event]);
- counter->destroy = sw_perf_counter_destroy;
+ if (!counter->parent) {
+ atomic_inc(&perf_swcounter_enabled[event]);
+ counter->destroy = sw_perf_counter_destroy;
+ }
pmu = &perf_ops_generic;
break;
}
@@ -3663,11 +3669,13 @@ done:
counter->pmu = pmu;
- atomic_inc(&nr_counters);
- if (counter->attr.mmap)
- atomic_inc(&nr_mmap_counters);
- if (counter->attr.comm)
- atomic_inc(&nr_comm_counters);
+ if (!counter->parent) {
+ atomic_inc(&nr_counters);
+ if (counter->attr.mmap)
+ atomic_inc(&nr_mmap_counters);
+ if (counter->attr.comm)
+ atomic_inc(&nr_comm_counters);
+ }
return counter;
}