linux-kernel - [PATCH v3 09/13] sched: Add deadline tracepoints

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Message-ID: <20251205131621.135513-10-gmonaco@redhat.com>
Date: Fri,  5 Dec 2025 14:16:17 +0100
From: Gabriele Monaco <gmonaco@...hat.com>
To: linux-kernel@...r.kernel.org,
	Steven Rostedt <rostedt@...dmis.org>,
	Nam Cao <namcao@...utronix.de>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-trace-kernel@...r.kernel.org
Cc: Gabriele Monaco <gmonaco@...hat.com>,
	Tomas Glozar <tglozar@...hat.com>,
	Juri Lelli <jlelli@...hat.com>,
	Clark Williams <williams@...hat.com>,
	John Kacur <jkacur@...hat.com>
Subject: [PATCH v3 09/13] sched: Add deadline tracepoints

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@...hat.com>
---

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