Messages in this thread Patch in this message | | | From | Benjamin Bouvier <> | Subject | [PATCH] sched/debug: Add tracepoint for RT throttling | Date | Fri, 14 Dec 2018 10:27:41 +0200 |
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As there is currently no information on which RT task is throttled, add a new tracepoint for debug purpose. By the way improve printk debugging message by adding task name, pid and cpu for which the throttle has been executed.
Signed-off-by: Benjamin Bouvier <benjamin.bouvier@nokia.com> --- include/trace/events/sched.h | 27 +++++++++++++++++++++++++++ kernel/sched/rt.c | 6 +++++- 2 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 9a4bdfadab07..09d3f7566f0a 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -587,6 +587,33 @@ TRACE_EVENT(sched_wake_idle_without_ipi, TP_printk("cpu=%d", __entry->cpu) ); + +/* + * Tracepoint for RT throttling task. + */ +TRACE_EVENT(sched_rt_throttling, + + TP_PROTO(struct task_struct *tsk, int cpu), + + TP_ARGS(tsk, cpu), + + TP_STRUCT__entry( + __array(char, comm, TASK_COMM_LEN) + __field(pid_t, pid) + __field(int, cpu) + ), + + TP_fast_assign( + memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN); + __entry->pid = tsk->pid; + __entry->cpu = cpu; + ), + + TP_printk("comm=%s pid=%d cpu=%d", + __entry->comm, __entry->pid, + __entry->cpu) +); + #endif /* _TRACE_SCHED_H */ /* This part must be outside protection */ diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index a21ea6021929..1a0ee91c9e16 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -6,6 +6,7 @@ #include "sched.h" #include "pelt.h" +#include <trace/events/sched.h> int sched_rr_timeslice = RR_TIMESLICE; int sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE; @@ -928,7 +929,10 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) */ if (likely(rt_b->rt_runtime)) { rt_rq->rt_throttled = 1; - printk_deferred_once("sched: RT throttling activated\n"); + printk_deferred_once( + "sched: RT throttling activated for task pid %d (%s) on cpu:%d\n", + rt_rq->rq->curr->pid, rt_rq->rq->curr->comm, rt_rq->rq->cpu); + trace_sched_rt_throttling(rt_rq->rq->curr, rt_rq->rq->cpu); } else { /* * In case we did anyway, make it go away, -- 2.10.2
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