Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH 2/6] sched,trace: Add a tracepoint for remote wakeups via polling | Date | Tue, 3 Jun 2014 17:29:48 -0700 |
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Remote wakeups of polling CPUs are a valuable performance improvement; add a tracepoint to make it much easier to verify that they're working.
Signed-off-by: Andy Lutomirski <luto@amacapital.net> --- include/trace/events/sched.h | 20 ++++++++++++++++++++ kernel/sched/core.c | 4 ++++ 2 files changed, 24 insertions(+)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 67e1bbf..08f8632 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -530,6 +530,26 @@ TRACE_EVENT(sched_swap_numa, __entry->dst_pid, __entry->dst_tgid, __entry->dst_ngid, __entry->dst_cpu, __entry->dst_nid) ); + +/* + * Tracepoint for waking a polling cpu without an IPI. + */ +TRACE_EVENT(sched_wake_polling_cpu, + + TP_PROTO(int cpu), + + TP_ARGS(cpu), + + TP_STRUCT__entry( + __field( int, cpu ) + ), + + TP_fast_assign( + __entry->cpu = cpu; + ), + + TP_printk("cpu=%d", __entry->cpu) +); #endif /* _TRACE_SCHED_H */ /* This part must be outside protection */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 321d800..18bebfc 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -564,6 +564,8 @@ void resched_task(struct task_struct *p) if (set_nr_and_not_polling(p)) smp_send_reschedule(cpu); + else + trace_sched_wake_polling_cpu(cpu); } void resched_cpu(int cpu) @@ -647,6 +649,8 @@ static void wake_up_idle_cpu(int cpu) smp_mb(); if (!tsk_is_polling(rq->idle)) smp_send_reschedule(cpu); + else + trace_sched_wake_polling_cpu(cpu); } static bool wake_up_full_nohz_cpu(int cpu) -- 1.9.3
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