[PATCH v5 3/3] sched/tp: Add new tracepoint to track compute energy computation

From: Qais Yousef
Date: Sat Sep 16 2023 - 19:43:59 EST


It was useful to track feec() placement decision and debug the spare
capacity and optimization issues vs uclamp_max.

Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Signed-off-by: Qais Yousef (Google) <qyousef@xxxxxxxxxxx>
---
include/trace/events/sched.h | 5 +++++
kernel/sched/core.c | 1 +
kernel/sched/fair.c | 7 ++++++-
3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index fbb99a61f714..a13d5d06be9d 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -735,6 +735,11 @@ DECLARE_TRACE(sched_update_nr_running_tp,
TP_PROTO(struct rq *rq, int change),
TP_ARGS(rq, change));

+DECLARE_TRACE(sched_compute_energy_tp,
+ TP_PROTO(struct task_struct *p, int dst_cpu, unsigned long energy,
+ unsigned long max_util, unsigned long busy_time),
+ TP_ARGS(p, dst_cpu, energy, max_util, busy_time));
+
#endif /* _TRACE_SCHED_H */

/* This part must be outside protection */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f39482d6a6e6..cc87627a7c63 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -114,6 +114,7 @@ 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);
EXPORT_TRACEPOINT_SYMBOL_GPL(sched_update_nr_running_tp);
+EXPORT_TRACEPOINT_SYMBOL_GPL(sched_compute_energy_tp);

DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0d0582e02409..fd7fd7b5aef2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7592,11 +7592,16 @@ compute_energy(struct energy_env *eenv, struct perf_domain *pd,
{
unsigned long max_util = eenv_pd_max_util(eenv, pd_cpus, p, dst_cpu);
unsigned long busy_time = eenv->pd_busy_time;
+ unsigned long energy;

if (dst_cpu >= 0)
busy_time = min(eenv->pd_cap, busy_time + eenv->task_busy_time);

- return em_cpu_energy(pd->em_pd, max_util, busy_time, eenv->cpu_cap);
+ energy = em_cpu_energy(pd->em_pd, max_util, busy_time, eenv->cpu_cap);
+
+ trace_sched_compute_energy_tp(p, dst_cpu, energy, max_util, busy_time);
+
+ return energy;
}

/*
--
2.34.1