sched/debug: Add new tracepoint to track cpu_capacity

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@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1598605249-72651-1-git-send-email-vincent.donnefort@arm.com

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2bf0af1..f516c18 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2044,6 +2044,7 @@ 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 fec25b9..c96a433 100644 (file)
--- 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 dd32d85..3dc415f 100644 (file)
--- 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 cec6cf9..aa4c622 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8108,6 +8108,8 @@ 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;
@@ -11321,6 +11323,18 @@ 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