Re: [PATCH v2 3/3] sched/tp: Add new tracepoint to track compute energy computation

From: Lukasz Luba
Date: Mon Feb 20 2023 - 06:22:55 EST


Hi Qais,

On 2/5/23 22:43, Qais Yousef wrote:
It was useful to track feec() placement decision and debug the spare
capacity and optimization issues vs uclamp_max.

Signed-off-by: Qais Yousef <qyousef@xxxxxxxxxxx>
---
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 4580fe3e1d0c..5f6dde9b892b 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 a8c3d92ff3f6..801e903c4307 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7295,11 +7295,16 @@ 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);

Could we also dump the max_util and busy_time?

+
+ return energy;
}
/*


IMO this one is really helpful. I hope it won't be an issue if we can
have it in this code path.

Regards,
Lukasz