sched, trace: Add a tracepoint for IPI-less remote wakeups (dfc68f29) · Commits · 戴 / test

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> Signed-off-by:

Peter Zijlstra <peterz@infradead.org> Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: umgwanakikbuti@gmail.com Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/16205aee116772aa686814f9b13bccb562108047.1401902905.git.luto@amacapital.net Signed-off-by:

Ingo Molnar <mingo@kernel.org>

include/trace/events/sched.h

+20 −0

Original line number	Diff line number	Diff line
		@@ -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 */

kernel/sched/core.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -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)

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