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Commit e6e6cc22 authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

nohz: Use enum code for tick stop failure tracing message 



It makes nohz tracing more lightweight, standard and easier to parse.

Examples:

       user_loop-2904  [007] d..1   517.701126: tick_stop: success=1 dependency=NONE
       user_loop-2904  [007] dn.1   518.021181: tick_stop: success=0 dependency=SCHED
    posix_timers-6142  [007] d..1  1739.027400: tick_stop: success=0 dependency=POSIX_TIMER
       user_loop-5463  [007] dN.1  1185.931939: tick_stop: success=0 dependency=PERF_EVENTS

Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Reviewed-by: default avatarChris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent d027d45d

include/linux/tick.h

+1 −0
Original line number Diff line number Diff line
@@ -104,6 +104,7 @@ enum tick_dep_bits { 
	TICK_DEP_BIT_CLOCK_UNSTABLE	= 3

};



#define TICK_DEP_MASK_NONE		0

#define TICK_DEP_MASK_POSIX_TIMER	(1 << TICK_DEP_BIT_POSIX_TIMER)

#define TICK_DEP_MASK_PERF_EVENTS	(1 << TICK_DEP_BIT_PERF_EVENTS)

#define TICK_DEP_MASK_SCHED		(1 << TICK_DEP_BIT_SCHED)

include/trace/events/timer.h

+31 −5
Original line number Diff line number Diff line
@@ -328,23 +328,49 @@ TRACE_EVENT(itimer_expire, 
);



#ifdef CONFIG_NO_HZ_COMMON



#define TICK_DEP_NAMES					\

		tick_dep_name(NONE)			\

		tick_dep_name(POSIX_TIMER)		\

		tick_dep_name(PERF_EVENTS)		\

		tick_dep_name(SCHED)			\

		tick_dep_name_end(CLOCK_UNSTABLE)



#undef tick_dep_name

#undef tick_dep_name_end



#define tick_dep_name(sdep) TRACE_DEFINE_ENUM(TICK_DEP_MASK_##sdep);

#define tick_dep_name_end(sdep)  TRACE_DEFINE_ENUM(TICK_DEP_MASK_##sdep);



TICK_DEP_NAMES



#undef tick_dep_name

#undef tick_dep_name_end



#define tick_dep_name(sdep) { TICK_DEP_MASK_##sdep, #sdep },

#define tick_dep_name_end(sdep) { TICK_DEP_MASK_##sdep, #sdep }



#define show_tick_dep_name(val)				\

	__print_symbolic(val, TICK_DEP_NAMES)



TRACE_EVENT(tick_stop,



	TP_PROTO(int success, char *error_msg),

	TP_PROTO(int success, int dependency),



	TP_ARGS(success, error_msg),

	TP_ARGS(success, dependency),



	TP_STRUCT__entry(

		__field( int ,		success	)

		__string( msg, 		error_msg )

		__field( int ,		dependency )

	),



	TP_fast_assign(

		__entry->success	= success;

		__assign_str(msg, error_msg);

		__entry->dependency	= dependency;

	),



	TP_printk("success=%s msg=%s",  __entry->success ? "yes" : "no", __get_str(msg))

	TP_printk("success=%d dependency=%s",  __entry->success, \

			show_tick_dep_name(__entry->dependency))

);

#endif

kernel/time/tick-sched.c

+9 −9
Original line number Diff line number Diff line
@@ -163,22 +163,22 @@ static unsigned long tick_dep_mask; 
static void trace_tick_dependency(unsigned long dep)

{

	if (dep & TICK_DEP_MASK_POSIX_TIMER) {

		trace_tick_stop(0, "posix timers running\n");

		trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);

		return;

	}



	if (dep & TICK_DEP_MASK_PERF_EVENTS) {

		trace_tick_stop(0, "perf events running\n");

		trace_tick_stop(0, TICK_DEP_MASK_PERF_EVENTS);

		return;

	}



	if (dep & TICK_DEP_MASK_SCHED) {

		trace_tick_stop(0, "more than 1 task in runqueue\n");

		trace_tick_stop(0, TICK_DEP_MASK_SCHED);

		return;

	}



	if (dep & TICK_DEP_MASK_CLOCK_UNSTABLE)

		trace_tick_stop(0, "unstable sched clock\n");

		trace_tick_stop(0, TICK_DEP_MASK_CLOCK_UNSTABLE);

}



static bool can_stop_full_tick(struct tick_sched *ts)
@@ -206,17 +206,17 @@ static bool can_stop_full_tick(struct tick_sched *ts) 
	}



	if (!sched_can_stop_tick()) {

		trace_tick_stop(0, "more than 1 task in runqueue\n");

		trace_tick_stop(0, TICK_DEP_MASK_SCHED);

		return false;

	}



	if (!posix_cpu_timers_can_stop_tick(current)) {

		trace_tick_stop(0, "posix timers running\n");

		trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);

		return false;

	}



	if (!perf_event_can_stop_tick()) {

		trace_tick_stop(0, "perf events running\n");

		trace_tick_stop(0, TICK_DEP_MASK_PERF_EVENTS);

		return false;

	}
@@ -228,7 +228,7 @@ static bool can_stop_full_tick(struct tick_sched *ts) 
	 * sched_clock_stable is set.

	 */

	if (!sched_clock_stable()) {

		trace_tick_stop(0, "unstable sched clock\n");

		trace_tick_stop(0, TICK_DEP_MASK_CLOCK_UNSTABLE);

		/*

		 * Don't allow the user to think they can get

		 * full NO_HZ with this machine.
@@ -821,7 +821,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, 


		ts->last_tick = hrtimer_get_expires(&ts->sched_timer);

		ts->tick_stopped = 1;

		trace_tick_stop(1, " ");

		trace_tick_stop(1, TICK_DEP_MASK_NONE);

	}



	/*