Commit-ID: b85c8b71bf8de36a88f338f406f02a8cb48c5c3b
Gitweb: https://git.kernel.org/tip/b85c8b71bf8de36a88f338f406f02a8cb48c5c3b
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 16 Jan 2018 20:51:06 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 6 Feb 2018 10:20:31 +0100
sched/core: Optimize ttwu_stat()
The whole of ttwu_stat() is guarded by a single schedstat_enabled(),
there is absolutely no point in then issuing another static_branch for
every single schedstat_inc() in there.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/core.c | 16 ++++++++--------
kernel/sched/stats.h | 2 ++
2 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ee420d7..b40540e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1630,16 +1630,16 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
#ifdef CONFIG_SMP
if (cpu == rq->cpu) {
- schedstat_inc(rq->ttwu_local);
- schedstat_inc(p->se.statistics.nr_wakeups_local);
+ __schedstat_inc(rq->ttwu_local);
+ __schedstat_inc(p->se.statistics.nr_wakeups_local);
} else {
struct sched_domain *sd;
- schedstat_inc(p->se.statistics.nr_wakeups_remote);
+ __schedstat_inc(p->se.statistics.nr_wakeups_remote);
rcu_read_lock();
for_each_domain(rq->cpu, sd) {
if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
- schedstat_inc(sd->ttwu_wake_remote);
+ __schedstat_inc(sd->ttwu_wake_remote);
break;
}
}
@@ -1647,14 +1647,14 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
}
if (wake_flags & WF_MIGRATED)
- schedstat_inc(p->se.statistics.nr_wakeups_migrate);
+ __schedstat_inc(p->se.statistics.nr_wakeups_migrate);
#endif /* CONFIG_SMP */
- schedstat_inc(rq->ttwu_count);
- schedstat_inc(p->se.statistics.nr_wakeups);
+ __schedstat_inc(rq->ttwu_count);
+ __schedstat_inc(p->se.statistics.nr_wakeups);
if (wake_flags & WF_SYNC)
- schedstat_inc(p->se.statistics.nr_wakeups_sync);
+ __schedstat_inc(p->se.statistics.nr_wakeups_sync);
}
static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
index baf500d..61500bb 100644
--- a/kernel/sched/stats.h
+++ b/kernel/sched/stats.h
@@ -31,6 +31,7 @@ rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
rq->rq_sched_info.run_delay += delta;
}
#define schedstat_enabled() static_branch_unlikely(&sched_schedstats)
+#define __schedstat_inc(var) do { var++; } while (0)
#define schedstat_inc(var) do { if (schedstat_enabled()) { var++; } } while (0)
#define schedstat_add(var, amt) do { if (schedstat_enabled()) { var += (amt); } } while (0)
#define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0)
@@ -48,6 +49,7 @@ static inline void
rq_sched_info_depart(struct rq *rq, unsigned long long delta)
{}
#define schedstat_enabled() 0
+#define __schedstat_inc(var) do { } while (0)
#define schedstat_inc(var) do { } while (0)
#define schedstat_add(var, amt) do { } while (0)
#define schedstat_set(var, val) do { } while (0)
--
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