Add trace points into enqueue_task() and dequeue_task(). They are useful to implement RV monitor which validates RT scheduling.
Signed-off-by: Nam Cao <[email protected]> --- Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Juri Lelli <[email protected]> Cc: Vincent Guittot <[email protected]> Cc: Dietmar Eggemann <[email protected]> Cc: Ben Segall <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Valentin Schneider <[email protected]> Cc: K Prateek Nayak <[email protected]> --- v2: Move the tracepoints to cover all task enqueue/dequeue, not just RT --- include/trace/events/sched.h | 13 +++++++++++++ kernel/sched/core.c | 8 +++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index c08893bde255..ec38928e61e7 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -898,6 +898,19 @@ DECLARE_TRACE(sched_set_need_resched, TP_PROTO(struct task_struct *tsk, int cpu, int tif), TP_ARGS(tsk, cpu, tif)); +/* + * The two trace points below may not work as expected for fair tasks due + * to delayed dequeue. See: + * https://lore.kernel.org/lkml/[email protected]/ + */ +DECLARE_TRACE(enqueue_task, + TP_PROTO(int cpu, struct task_struct *task), + TP_ARGS(cpu, task)); + +DECLARE_TRACE(dequeue_task, + TP_PROTO(int cpu, struct task_struct *task), + TP_ARGS(cpu, task)); + #endif /* _TRACE_SCHED_H */ /* This part must be outside protection */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b485e0639616..553c08a63395 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2077,6 +2077,8 @@ unsigned long get_wchan(struct task_struct *p) void enqueue_task(struct rq *rq, struct task_struct *p, int flags) { + trace_enqueue_task_tp(rq->cpu, p); + if (!(flags & ENQUEUE_NOCLOCK)) update_rq_clock(rq); @@ -2119,7 +2121,11 @@ inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags) * and mark the task ->sched_delayed. */ uclamp_rq_dec(rq, p); - return p->sched_class->dequeue_task(rq, p, flags); + if (p->sched_class->dequeue_task(rq, p, flags)) { + trace_dequeue_task_tp(rq->cpu, p); + return true; + } + return false; } void activate_task(struct rq *rq, struct task_struct *p, int flags) -- 2.39.5
