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Commit 15f5eaa7 authored by Dietmar Eggemann's avatar Dietmar Eggemann Committed by Chris Redpath
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ANDROID: sched/events: Introduce cfs_rq load tracking trace event 



The trace event keys load and util (utilization) are mapped to:

 (1) load : cfs_rq->runnable_load_avg

 (2) util : cfs_rq->avg.util_avg

To let this trace event work for configurations w/ and w/o group
scheduling support for cfs (CONFIG_FAIR_GROUP_SCHED) the following
special handling is necessary for non-existent key=value pairs:

 path = "(null)" : In case of !CONFIG_FAIR_GROUP_SCHED.

The following list shows examples of the key=value pairs in different
configurations for:

 (1) a root task_group:

     cpu=4 path=/ load=6 util=331

 (2) a task_group:

     cpu=1 path=/tg1/tg11/tg111 load=538 util=522

 (3) an autogroup:

     cpu=3 path=/autogroup-18 load=997 util=517

 (4) w/o CONFIG_FAIR_GROUP_SCHED:

     cpu=0 path=(null) load=314 util=289

The trace event is only defined for CONFIG_SMP.

The helper function __trace_sched_path() can be used to get the length
parameter of the dynamic array (path == NULL) and to copy the path into
it (path != NULL).

Signed-off-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
Change-Id: Iae08075d889dd772c8d2e1a15dc2ca6589e5640e
Signed-off-by: default avatarChris Redpath <chris.redpath@arm.com>
parent f8ddcacd

include/trace/events/sched.h

+63 −0
Original line number Diff line number Diff line
@@ -570,6 +570,69 @@ TRACE_EVENT(sched_wake_idle_without_ipi, 


	TP_printk("cpu=%d", __entry->cpu)

);



#ifdef CONFIG_SMP

#ifdef CREATE_TRACE_POINTS

static inline

int __trace_sched_cpu(struct cfs_rq *cfs_rq)

{

#ifdef CONFIG_FAIR_GROUP_SCHED

	struct rq *rq = cfs_rq->rq;

#else

	struct rq *rq = container_of(cfs_rq, struct rq, cfs);

#endif

	return cpu_of(rq);

}



static inline

int __trace_sched_path(struct cfs_rq *cfs_rq, char *path, int len)

{

#ifdef CONFIG_FAIR_GROUP_SCHED

	int l = path ? len : 0;



	if (task_group_is_autogroup(cfs_rq->tg))

		return autogroup_path(cfs_rq->tg, path, l) + 1;

	else

		return cgroup_path(cfs_rq->tg->css.cgroup, path, l) + 1;

#else

	if (path)

		strcpy(path, "(null)");



	return strlen("(null)");

#endif

}



#endif /* CREATE_TRACE_POINTS */



/*

 * Tracepoint for cfs_rq load tracking:

 */

TRACE_EVENT(sched_load_cfs_rq,



	TP_PROTO(struct cfs_rq *cfs_rq),



	TP_ARGS(cfs_rq),



	TP_STRUCT__entry(

		__field(	int,		cpu			)

		__dynamic_array(char,		path,

				__trace_sched_path(cfs_rq, NULL, 0)	)

		__field(	unsigned long,	load			)

		__field(	unsigned long,	util			)

	),



	TP_fast_assign(

		__entry->cpu	= __trace_sched_cpu(cfs_rq);

		__trace_sched_path(cfs_rq, __get_dynamic_array(path),

				   __get_dynamic_array_len(path));

		__entry->load	= cfs_rq->runnable_load_avg;

		__entry->util	= cfs_rq->avg.util_avg;

	),



	TP_printk("cpu=%d path=%s load=%lu util=%lu", __entry->cpu,

		  __get_str(path), __entry->load, __entry->util)

);

#endif /* CONFIG_SMP */

#endif /* _TRACE_SCHED_H */



/* This part must be outside protection */

kernel/sched/fair.c

+9 −0
Original line number Diff line number Diff line
@@ -3023,6 +3023,9 @@ ___update_load_avg(u64 now, int cpu, struct sched_avg *sa, 
	}

	sa->util_avg = sa->util_sum / (LOAD_AVG_MAX - 1024 + sa->period_contrib);



	if (cfs_rq)

		trace_sched_load_cfs_rq(cfs_rq);



	return 1;

}
@@ -3266,6 +3269,8 @@ static inline int propagate_entity_load_avg(struct sched_entity *se) 
	update_tg_cfs_util(cfs_rq, se);

	update_tg_cfs_load(cfs_rq, se);



	trace_sched_load_cfs_rq(cfs_rq);



	return 1;

}
@@ -3427,6 +3432,8 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s 
	set_tg_cfs_propagate(cfs_rq);



	cfs_rq_util_change(cfs_rq);



	trace_sched_load_cfs_rq(cfs_rq);

}



/**
@@ -3447,6 +3454,8 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s 
	set_tg_cfs_propagate(cfs_rq);



	cfs_rq_util_change(cfs_rq);



	trace_sched_load_cfs_rq(cfs_rq);

}



/* Add the load generated by se into cfs_rq's load average */