Commit-ID: dfc68f29ae67f2a6e799b44e6a4eb3417dffbfcd Gitweb: http://git.kernel.org/tip/dfc68f29ae67f2a6e799b44e6a4eb3417dffbfcd Author: Andy Lutomirski <[email protected]> AuthorDate: Wed, 4 Jun 2014 10:31:15 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Thu, 5 Jun 2014 12:09:50 +0200
sched, trace: Add a tracepoint for IPI-less remote wakeups 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 <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: David Ahern <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/16205aee116772aa686814f9b13bccb562108047.1401902905.git.l...@amacapital.net Signed-off-by: Ingo Molnar <[email protected]> --- 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..0a68d5a 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_idle_without_ipi, + + 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 5976ca5..e4c0ddd 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_idle_without_ipi(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_idle_without_ipi(cpu); } static bool wake_up_full_nohz_cpu(int cpu) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
