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

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Message-Id: <20230129161444.1674958-4-qyousef@layalina.io>
Date:   Sun, 29 Jan 2023 16:14:44 +0000
From:   Qais Yousef <qyousef@...alina.io>
To:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>
Cc:     linux-kernel@...r.kernel.org, Lukasz Luba <lukasz.luba@....com>,
        Wei Wang <wvw@...gle.com>, Xuewen Yan <xuewen.yan94@...il.com>,
        Hank <han.lin@...iatek.com>,
        Jonathan JMChen <Jonathan.JMChen@...iatek.com>,
        Qais Yousef <qyousef@...alina.io>
Subject: [PATCH 3/3] sched/tp: 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@...alina.io>
---
 include/trace/events/sched.h | 4 ++++
 kernel/sched/core.c          | 1 +
 kernel/sched/fair.c          | 7 ++++++-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index fbb99a61f714..20cc884f72ff 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -735,6 +735,10 @@ 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),
+	TP_ARGS(p, dst_cpu, energy));
+
 #endif /* _TRACE_SCHED_H */
 
 /* This part must be outside protection */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 03b8529db73f..79ad6b8ea93e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -110,6 +110,7 @@ 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 3521aad67aa0..3b55dbb0fcfe 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7303,11 +7303,16 @@ 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);
+
+	return energy;
 }
 
 /*
-- 
2.25.1