sched/debug: Add new tracepoint to track compute energy computation

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

Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230916232955.2099394-4-qyousef@layalina.io

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index fbb99a61f714cbebb91ba9280ce44f812ece32de..a13d5d06be9d6c0ab4ebe0acae095c8d02a3b0b2 100644 (file)
--- 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 84881a582847f04d34989602af8e28f741165203..324980e3d2e51423748d412e02496081d6127838 100644 (file)
--- 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 284b0abe7f9b436abdd50520fac4246c2f98dd77..e2a69af8be36e264efdbc739b7b54be76dde0df4 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7600,11 +7600,16 @@ 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;
 }
 
 /*