Re: [PATCH v3 09/13] sched: Add deadline tracepoints

Phil Auld
2025-12-05T13:41:46Z

On Fri, Dec 05, 2025 at 02:16:17PM +0100 Gabriele Monaco wrote:
> Add the following tracepoints:
>
> * sched_dl_throttle(dl_se, cpu):
> Called when a deadline entity is throttled
> * sched_dl_replenish(dl_se, cpu):
> Called when a deadline entity's runtime is replenished
> * sched_dl_server_start(dl_se, cpu):
> Called when a deadline server is started
> * sched_dl_server_stop(dl_se, cpu):
> Called when a deadline server is stopped
>
> Those tracepoints can be useful to validate the deadline scheduler with
> RV and are not exported to tracefs.
>
> Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

These seem like they might be useful outside of the RV context as well.

Reviewed-by: Phil Auld <pauld@redhat.com>

Cheers,
Phil

> ---
>
> Notes:
> V3:
> * Rename dl argument to dl_se in tracepoints
>
> include/trace/events/sched.h | 16 ++++++++++++++++
> kernel/sched/core.c | 4 ++++
> kernel/sched/deadline.c | 7 +++++++
> 3 files changed, 27 insertions(+)
>
> diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
> index 7b2645b50e78..366b2e8ec40c 100644
> --- a/include/trace/events/sched.h
> +++ b/include/trace/events/sched.h
> @@ -896,6 +896,22 @@ DECLARE_TRACE(sched_set_need_resched,
> TP_PROTO(struct task_struct *tsk, int cpu, int tif),
> TP_ARGS(tsk, cpu, tif));
>
> +DECLARE_TRACE(sched_dl_throttle,
> + TP_PROTO(struct sched_dl_entity *dl_se, int cpu),
> + TP_ARGS(dl_se, cpu));
> +
> +DECLARE_TRACE(sched_dl_replenish,
> + TP_PROTO(struct sched_dl_entity *dl_se, int cpu),
> + TP_ARGS(dl_se, cpu));
> +
> +DECLARE_TRACE(sched_dl_server_start,
> + TP_PROTO(struct sched_dl_entity *dl_se, int cpu),
> + TP_ARGS(dl_se, cpu));
> +
> +DECLARE_TRACE(sched_dl_server_stop,
> + TP_PROTO(struct sched_dl_entity *dl_se, int cpu),
> + TP_ARGS(dl_se, cpu));
> +
> #endif /* _TRACE_SCHED_H */
>
> /* This part must be outside protection */
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 5516778c19eb..3aed0ed6f2e9 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -122,6 +122,10 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(sched_compute_energy_tp);
> EXPORT_TRACEPOINT_SYMBOL_GPL(sched_entry_tp);
> EXPORT_TRACEPOINT_SYMBOL_GPL(sched_exit_tp);
> EXPORT_TRACEPOINT_SYMBOL_GPL(sched_set_need_resched_tp);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(sched_dl_throttle_tp);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(sched_dl_replenish_tp);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(sched_dl_server_start_tp);
> +EXPORT_TRACEPOINT_SYMBOL_GPL(sched_dl_server_stop_tp);
>
> DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
> DEFINE_PER_CPU(struct rnd_state, sched_rnd_state);
> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
> index 319439fe1870..2192e9f42e02 100644
> --- a/kernel/sched/deadline.c
> +++ b/kernel/sched/deadline.c
> @@ -733,6 +733,7 @@ static inline void replenish_dl_new_period(struct sched_dl_entity *dl_se,
> dl_se->dl_throttled = 1;
> dl_se->dl_defer_armed = 1;
> }
> + trace_sched_dl_replenish_tp(dl_se, cpu_of(rq));
> }
>
> /*
> @@ -850,6 +851,8 @@ static void replenish_dl_entity(struct sched_dl_entity *dl_se)
> if (dl_se->dl_throttled)
> dl_se->dl_throttled = 0;
>
> + trace_sched_dl_replenish_tp(dl_se, cpu_of(rq));
> +
> /*
> * If this is the replenishment of a deferred reservation,
> * clear the flag and return.
> @@ -1341,6 +1344,7 @@ static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se)
> dl_time_before(rq_clock(rq), dl_next_period(dl_se))) {
> if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(dl_se)))
> return;
> + trace_sched_dl_throttle_tp(dl_se, cpu_of(rq));
> dl_se->dl_throttled = 1;
> if (dl_se->runtime > 0)
> dl_se->runtime = 0;
> @@ -1504,6 +1508,7 @@ static void update_curr_dl_se(struct rq *rq, struct sched_dl_entity *dl_se, s64
>
> throttle:
> if (dl_runtime_exceeded(dl_se) || dl_se->dl_yielded) {
> + trace_sched_dl_throttle_tp(dl_se, cpu_of(rq));
> dl_se->dl_throttled = 1;
>
> /* If requested, inform the user about runtime overruns. */
> @@ -1795,6 +1800,7 @@ void dl_server_start(struct sched_dl_entity *dl_se)
> if (WARN_ON_ONCE(!cpu_online(cpu_of(rq))))
> return;
>
> + trace_sched_dl_server_start_tp(dl_se, cpu_of(rq));
> dl_se->dl_server_active = 1;
> enqueue_dl_entity(dl_se, ENQUEUE_WAKEUP);
> if (!dl_task(dl_se->rq->curr) || dl_entity_preempt(dl_se, &rq->curr->dl))
> @@ -1806,6 +1812,7 @@ void dl_server_stop(struct sched_dl_entity *dl_se)
> if (!dl_server(dl_se) || !dl_server_active(dl_se))
> return;
>
> + trace_sched_dl_server_stop_tp(dl_se, cpu_of(dl_se->rq));
> dequeue_dl_entity(dl_se, DEQUEUE_SLEEP);
> hrtimer_try_to_cancel(&dl_se->dl_timer);
> dl_se->dl_defer_armed = 0;
> --
> 2.52.0
>
>

--