[PATCH v5 09/15] sched: Add task enqueue/dequeue trace points
From: Gabriele Monaco <gmonaco@redhat.com>
Date: 2026-01-22 15:56:13
Also in:
lkml
Subsystem:
scheduler, the rest, tracing · Maintainers:
Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
From: Nam Cao <redacted>
Add trace points into enqueue_task() and dequeue_task().
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nam Cao <redacted>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
Notes:
V5:
* Do not fire enqueue tracepoint for delayed enqueues
include/trace/events/sched.h | 13 +++++++++++++
kernel/sched/core.c | 10 +++++++++-
kernel/sched/sched.h | 2 ++
3 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 366b2e8ec40c..f4e1d3554e3e 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h@@ -912,6 +912,19 @@ DECLARE_TRACE(sched_dl_server_stop, TP_PROTO(struct sched_dl_entity *dl_se, int cpu), TP_ARGS(dl_se, cpu)); +/* + * The two trace points below may not work as expected for fair tasks due + * to delayed dequeue. See: + * https://lore.kernel.org/lkml/179674c6-f82a-4718-ace2-67b5e672fdee@amd.com/ + */ +DECLARE_TRACE(sched_enqueue, + TP_PROTO(struct task_struct *tsk, int cpu), + TP_ARGS(tsk, cpu)); + +DECLARE_TRACE(sched_dequeue, + TP_PROTO(struct task_struct *tsk, int cpu), + TP_ARGS(tsk, cpu)); + #endif /* _TRACE_SCHED_H */ /* This part must be outside protection */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f6293fa02fb7..c885d7885172 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c@@ -2087,6 +2087,9 @@ unsigned long get_wchan(struct task_struct *p) void enqueue_task(struct rq *rq, struct task_struct *p, int flags) { + if (trace_sched_enqueue_tp_enabled() && !(flags & ENQUEUE_DELAYED)) + trace_sched_enqueue_tp(p, rq->cpu); + if (!(flags & ENQUEUE_NOCLOCK)) update_rq_clock(rq);
@@ -2114,6 +2117,8 @@ void enqueue_task(struct rq *rq, struct task_struct *p, int flags) */ inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags) { + int ret; + if (sched_core_enabled(rq)) sched_core_dequeue(rq, p, flags);
@@ -2131,7 +2136,10 @@ inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags) */ uclamp_rq_dec(rq, p); rq->queue_mask |= p->sched_class->queue_mask; - return p->sched_class->dequeue_task(rq, p, flags); + ret = p->sched_class->dequeue_task(rq, p, flags); + if (trace_sched_dequeue_tp_enabled() && !(flags & DEQUEUE_SLEEP)) + trace_sched_dequeue_tp(p, rq->cpu); + return ret; } void activate_task(struct rq *rq, struct task_struct *p, int flags)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e885a935b716..8465472b40fa 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h@@ -2918,6 +2918,8 @@ static inline void sub_nr_running(struct rq *rq, unsigned count) static inline void __block_task(struct rq *rq, struct task_struct *p) { + trace_sched_dequeue_tp(p, rq->cpu); + if (p->sched_contributes_to_load) rq->nr_uninterruptible++;
--
2.52.0