The new tracepoint allows us to track the changes in overutilized status. Overutilized status is associated with EAS. It indicates that the system is in high performance state. EAS is disabled when the system is in this state since there's not much energy savings while high performance tasks are pushing the system to the limit and it's better to default to the spreading behavior of the scheduler.
This tracepoint helps understanding and debugging the conditions under which this happens. Signed-off-by: Qais Yousef <[email protected]> --- include/trace/events/sched.h | 4 ++++ kernel/sched/fair.c | 7 ++++++- 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index cbcb47972232..0cf42d13d6c4 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -600,6 +600,10 @@ DECLARE_TRACE(pelt_se, TP_PROTO(int cpu, const char *path, struct sched_entity *se), TP_ARGS(cpu, path, se)); +DECLARE_TRACE(sched_overutilized, + TP_PROTO(int overutilized), + TP_ARGS(overutilized)); + #endif /* _TRACE_SCHED_H */ /* This part must be outside protection */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 81036c34fd29..494032220fe7 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4965,8 +4965,10 @@ static inline bool cpu_overutilized(int cpu) static inline void update_overutilized_status(struct rq *rq) { - if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu)) + if (!READ_ONCE(rq->rd->overutilized) && cpu_overutilized(rq->cpu)) { WRITE_ONCE(rq->rd->overutilized, SG_OVERUTILIZED); + trace_sched_overutilized(1); + } } #else static inline void update_overutilized_status(struct rq *rq) { } @@ -8330,8 +8332,11 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd /* Update over-utilization (tipping point, U >= 0) indicator */ WRITE_ONCE(rd->overutilized, sg_status & SG_OVERUTILIZED); + + trace_sched_overutilized(!!(sg_status & SG_OVERUTILIZED)); } else if (sg_status & SG_OVERUTILIZED) { WRITE_ONCE(env->dst_rq->rd->overutilized, SG_OVERUTILIZED); + trace_sched_overutilized(1); } } -- 2.17.1
