[PATCH] sched/debug: Add new tracepoint to track cpu_capacity

From: vincent . donnefort
Date: Thu Aug 27 2020 - 11:37:02 EST


From: Vincent Donnefort <vincent.donnefort@xxxxxxx>

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@xxxxxxx>

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..e11f724 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 +11320,12 @@ 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 ? rq->cpu_capacity : -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