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Message-Id: <20231221150238.856960-1-wudaemon@163.com>
Date: Thu, 21 Dec 2023 15:02:38 +0000
From: Junwen Wu <wudaemon@....com>
To: mingo@...hat.com,
laoar.shao@...il.com,
peterz@...radead.org,
juri.lelli@...hat.com,
vincent.guittot@...aro.org,
dietmar.eggemann@....com,
rostedt@...dmis.org,
bsegall@...gle.com
Cc: mgorman@...e.de,
bristot@...hat.com,
vschneid@...hat.com,
linux-kernel@...r.kernel.org,
Junwen Wu <wudaemon@....com>
Subject: [PATCH v2] sched/rt: Fix rt task's sched latency statistics error in sched_stat_wait trace_point
When enable sched_stat_wait trace_point, some rt tasks sched latency
so long, like this:
sched_stat_wait: comm=rcu_preempt pid=14 delay=4936139545261 [ns]
Rt task has low latency, it must have a bug. When rt task balance off
source cpu, dequeue operation not update the sched_statistics, so follow
update_stats_wait_end_fair update method.
Signed-off-by: Junwen Wu <wudaemon@....com>
---
Changes since v1:
https://lore.kernel.org/all/20231218150322.788382-1-wudaemon@163.com/
kernel/sched/rt.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 6aaf0a3d6081..6a2600213991 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1360,12 +1360,19 @@ update_stats_dequeue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
int flags)
{
struct task_struct *p = NULL;
+ struct rq *rq = rq_of_rt_se(rt_se);
if (!schedstat_enabled())
return;
if (rt_entity_is_task(rt_se))
p = rt_task_of(rt_se);
+ /*
+ * Mark the end of the wait period
+ * if dequeueing a waiting task.
+ */
+ if (p && (p != rq->curr))
+ update_stats_wait_end_rt(rt_rq, rt_se);
if ((flags & DEQUEUE_SLEEP) && p) {
unsigned int state;
--
2.34.1
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