linux-kernel - [PATCH v2] sched/debug: Add new tracepoint to track cpu

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Message-Id: <1598605249-72651-1-git-send-email-vincent.donnefort@arm.com>
Date:   Fri, 28 Aug 2020 10:00:49 +0100
From:   vincent.donnefort@....com
To:     mingo@...hat.com, peterz@...radead.org, vincent.guittot@...aro.org
Cc:     linux-kernel@...r.kernel.org, dietmar.eggemann@....com,
        valentin.schneider@....com, qais.yousef@....com,
        Vincent Donnefort <vincent.donnefort@....com>
Subject: [PATCH v2] sched/debug: Add new tracepoint to track cpu_capacity

From: Vincent Donnefort <vincent.donnefort@....com>

rq->cpu_capacity is a key element in several scheduler parts, such as EAS
task placement and load balancing. Tracking this value enables testing
and/or debugging by a toolkit.

Signed-off-by: Vincent Donnefort <vincent.donnefort@....com>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 021ad7b..7e19d59 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2055,6 +2055,7 @@ const struct sched_avg *sched_trace_rq_avg_dl(struct rq *rq);
 const struct sched_avg *sched_trace_rq_avg_irq(struct rq *rq);
 
 int sched_trace_rq_cpu(struct rq *rq);
+int sched_trace_rq_cpu_capacity(struct rq *rq);
 int sched_trace_rq_nr_running(struct rq *rq);
 
 const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 8ab48b3..f94ddd1 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -630,6 +630,10 @@ DECLARE_TRACE(pelt_se_tp,
 	TP_PROTO(struct sched_entity *se),
 	TP_ARGS(se));
 
+DECLARE_TRACE(sched_cpu_capacity_tp,
+	TP_PROTO(struct rq *rq),
+	TP_ARGS(rq));
+
 DECLARE_TRACE(sched_overutilized_tp,
 	TP_PROTO(struct root_domain *rd, bool overutilized),
 	TP_ARGS(rd, overutilized));
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 06b0a40..e468271 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -36,6 +36,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_rt_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_dl_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_se_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_cpu_capacity_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_overutilized_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_cfs_tp);
 EXPORT_TRACEPOINT_SYMBOL_GPL(sched_util_est_se_tp);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 44f7a0b..27f4392 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8116,6 +8116,8 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu)
 		capacity = 1;
 
 	cpu_rq(cpu)->cpu_capacity = capacity;
+	trace_sched_cpu_capacity_tp(cpu_rq(cpu));
+
 	sdg->sgc->capacity = capacity;
 	sdg->sgc->min_capacity = capacity;
 	sdg->sgc->max_capacity = capacity;
@@ -11318,6 +11320,18 @@ int sched_trace_rq_cpu(struct rq *rq)
 }
 EXPORT_SYMBOL_GPL(sched_trace_rq_cpu);
 
+int sched_trace_rq_cpu_capacity(struct rq *rq)
+{
+	return rq ?
+#ifdef CONFIG_SMP
+		rq->cpu_capacity
+#else
+		SCHED_CAPACITY_SCALE
+#endif
+		: -1;
+}
+EXPORT_SYMBOL_GPL(sched_trace_rq_cpu_capacity);
+
 const struct cpumask *sched_trace_rd_span(struct root_domain *rd)
 {
 #ifdef CONFIG_SMP
-- 
2.7.4