From: Morten Rasmussen morten.rasmussen@arm.com
Adds ftrace events for key variables related to the entity load-tracking to help debugging scheduler behaviour. Allows tracing of load contribution and runqueue residency ratio for both entities and runqueues as well as entity CPU usage ratio.
Signed-off-by: Morten Rasmussen morten.rasmussen@arm.com --- include/trace/events/sched.h | 125 ++++++++++++++++++++++++++++++++++++++++++ kernel/sched/fair.c | 7 +++ 2 files changed, 132 insertions(+)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 5a8671e..847eb76 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -430,6 +430,131 @@ TRACE_EVENT(sched_pi_setprio, __entry->oldprio, __entry->newprio) );
+/* + * Tracepoint for showing tracked load contribution. + */ +TRACE_EVENT(sched_task_load_contrib, + + TP_PROTO(struct task_struct *tsk, unsigned long load_contrib), + + TP_ARGS(tsk, load_contrib), + + TP_STRUCT__entry( + __array(char, comm, TASK_COMM_LEN) + __field(pid_t, pid) + __field(unsigned long, load_contrib) + ), + + TP_fast_assign( + memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN); + __entry->pid = tsk->pid; + __entry->load_contrib = load_contrib; + ), + + TP_printk("comm=%s pid=%d load_contrib=%lu", + __entry->comm, __entry->pid, + __entry->load_contrib) +); + +/* + * Tracepoint for showing tracked task runnable ratio [0..1023]. + */ +TRACE_EVENT(sched_task_runnable_ratio, + + TP_PROTO(struct task_struct *tsk, unsigned long ratio), + + TP_ARGS(tsk, ratio), + + TP_STRUCT__entry( + __array(char, comm, TASK_COMM_LEN) + __field(pid_t, pid) + __field(unsigned long, ratio) + ), + + TP_fast_assign( + memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN); + __entry->pid = tsk->pid; + __entry->ratio = ratio; + ), + + TP_printk("comm=%s pid=%d ratio=%lu", + __entry->comm, __entry->pid, + __entry->ratio) +); + +/* + * Tracepoint for showing tracked rq runnable ratio [0..1023]. + */ +TRACE_EVENT(sched_rq_runnable_ratio, + + TP_PROTO(int cpu, unsigned long ratio), + + TP_ARGS(cpu, ratio), + + TP_STRUCT__entry( + __field(int, cpu) + __field(unsigned long, ratio) + ), + + TP_fast_assign( + __entry->cpu = cpu; + __entry->ratio = ratio; + ), + + TP_printk("cpu=%d ratio=%lu", + __entry->cpu, + __entry->ratio) +); + +/* + * Tracepoint for showing tracked rq runnable load. + */ +TRACE_EVENT(sched_rq_runnable_load, + + TP_PROTO(int cpu, u64 load), + + TP_ARGS(cpu, load), + + TP_STRUCT__entry( + __field(int, cpu) + __field(u64, load) + ), + + TP_fast_assign( + __entry->cpu = cpu; + __entry->load = load; + ), + + TP_printk("cpu=%d load=%llu", + __entry->cpu, + __entry->load) +); + +/* + * Tracepoint for showing tracked task cpu usage ratio [0..1023]. + */ +TRACE_EVENT(sched_task_usage_ratio, + + TP_PROTO(struct task_struct *tsk, unsigned long ratio), + + TP_ARGS(tsk, ratio), + + TP_STRUCT__entry( + __array(char, comm, TASK_COMM_LEN) + __field(pid_t, pid) + __field(unsigned long, ratio) + ), + + TP_fast_assign( + memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN); + __entry->pid = tsk->pid; + __entry->ratio = ratio; + ), + + TP_printk("comm=%s pid=%d ratio=%lu", + __entry->comm, __entry->pid, + __entry->ratio) +); #endif /* _TRACE_SCHED_H */
/* This part must be outside protection */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8f0f3b9..0be53be 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1192,9 +1192,11 @@ static inline void __update_task_entity_contrib(struct sched_entity *se) contrib = se->avg.runnable_avg_sum * scale_load_down(se->load.weight); contrib /= (se->avg.runnable_avg_period + 1); se->avg.load_avg_contrib = scale_load(contrib); + trace_sched_task_load_contrib(task_of(se), se->avg.load_avg_contrib); contrib = se->avg.runnable_avg_sum * scale_load_down(NICE_0_LOAD); contrib /= (se->avg.runnable_avg_period + 1); se->avg.load_avg_ratio = scale_load(contrib); + trace_sched_task_runnable_ratio(task_of(se), se->avg.load_avg_ratio); }
/* Compute the current contribution to load_avg by se, return any delta */ @@ -1286,9 +1288,14 @@ static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update)
static inline void update_rq_runnable_avg(struct rq *rq, int runnable) { + u32 contrib; __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable, runnable); __update_tg_runnable_avg(&rq->avg, &rq->cfs); + contrib = rq->avg.runnable_avg_sum * scale_load_down(1024); + contrib /= (rq->avg.runnable_avg_period + 1); + trace_sched_rq_runnable_ratio(cpu_of(rq), scale_load(contrib)); + trace_sched_rq_runnable_load(cpu_of(rq), rq->cfs.runnable_load_avg); }
/* Add the load generated by se into cfs_rq's child load-average */