@@ -1273,6 +1273,129 @@ static void __delist_rt_entity(struct sched_rt_entity *rt_se, struct rt_prio_arr
rt_se->on_list = 0;
}
+#ifdef CONFIG_RT_GROUP_SCHED
+static inline void
+__schedstats_from_sched_rt_entity(struct sched_rt_entity *rt_se,
+ struct sched_statistics **stats)
+{
+ struct task_struct *p;
+ struct task_group *tg;
+ struct rt_rq *rt_rq;
+ int cpu;
+
+ if (rt_entity_is_task(rt_se)) {
+ p = rt_task_of(rt_se);
+ *stats = &p->stats;
+ } else {
+ rt_rq = group_rt_rq(rt_se);
+ tg = rt_rq->tg;
+ cpu = cpu_of(rq_of_rt_rq(rt_rq));
+ *stats = tg->stats[cpu];
+ }
+}
+
+#else
+
+static inline void
+__schedstats_from_sched_rt_entity(struct sched_rt_entity *rt_se,
+ struct sched_statistics **stats)
+{
+ struct task_struct *p;
+
+ p = rt_task_of(rt_se);
+ *stats = &p->stats;
+}
+
+#endif
+
+static inline void
+update_stats_wait_start_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+ struct sched_statistics *stats = NULL;
+ struct task_struct *p = NULL;
+
+ if (!schedstat_enabled())
+ return;
+
+ if (rt_entity_is_task(rt_se))
+ p = rt_task_of(rt_se);
+
+ __schedstats_from_sched_rt_entity(rt_se, &stats);
+
+ __update_stats_wait_start(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_sleeper_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+ struct sched_statistics *stats = NULL;
+ struct task_struct *p = NULL;
+
+ if (!schedstat_enabled())
+ return;
+
+ if (rt_entity_is_task(rt_se))
+ p = rt_task_of(rt_se);
+
+ __schedstats_from_sched_rt_entity(rt_se, &stats);
+
+ __update_stats_enqueue_sleeper(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_enqueue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
+ int flags)
+{
+ if (!schedstat_enabled())
+ return;
+
+ if (flags & ENQUEUE_WAKEUP)
+ update_stats_enqueue_sleeper_rt(rt_rq, rt_se);
+}
+
+static inline void
+update_stats_wait_end_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
+{
+ struct sched_statistics *stats = NULL;
+ struct task_struct *p = NULL;
+
+ if (!schedstat_enabled())
+ return;
+
+ if (rt_entity_is_task(rt_se))
+ p = rt_task_of(rt_se);
+
+ __schedstats_from_sched_rt_entity(rt_se, &stats);
+
+ __update_stats_wait_end(rq_of_rt_rq(rt_rq), p, stats);
+}
+
+static inline void
+update_stats_dequeue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
+ int flags)
+{
+ struct task_struct *p = NULL;
+
+ if (!schedstat_enabled())
+ return;
+
+ if (rt_entity_is_task(rt_se))
+ p = rt_task_of(rt_se);
+
+ if ((flags & DEQUEUE_SLEEP) && p) {
+ unsigned int state;
+
+ state = READ_ONCE(p->__state);
+ if (state & TASK_INTERRUPTIBLE)
+ __schedstat_set(p->stats.sleep_start,
+ rq_clock(rq_of_rt_rq(rt_rq)));
+
+ if (state & TASK_UNINTERRUPTIBLE)
+ __schedstat_set(p->stats.block_start,
+ rq_clock(rq_of_rt_rq(rt_rq)));
+ }
+}
+
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
@@ -1346,6 +1469,8 @@ static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct rq *rq = rq_of_rt_se(rt_se);
+ update_stats_enqueue_rt(rt_rq_of_se(rt_se), rt_se, flags);
+
dequeue_rt_stack(rt_se, flags);
for_each_sched_rt_entity(rt_se)
__enqueue_rt_entity(rt_se, flags);
@@ -1356,6 +1481,8 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct rq *rq = rq_of_rt_se(rt_se);
+ update_stats_dequeue_rt(rt_rq_of_se(rt_se), rt_se, flags);
+
dequeue_rt_stack(rt_se, flags);
for_each_sched_rt_entity(rt_se) {
@@ -1378,6 +1505,9 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
if (flags & ENQUEUE_WAKEUP)
rt_se->timeout = 0;
+ check_schedstat_required();
+ update_stats_wait_start_rt(rt_rq_of_se(rt_se), rt_se);
+
enqueue_rt_entity(rt_se, flags);
if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
@@ -1578,7 +1708,12 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flag
static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first)
{
+ struct sched_rt_entity *rt_se = &p->rt;
+ struct rt_rq *rt_rq = &rq->rt;
+
p->se.exec_start = rq_clock_task(rq);
+ if (on_rt_rq(&p->rt))
+ update_stats_wait_end_rt(rt_rq, rt_se);
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
@@ -1652,6 +1787,12 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
+ struct sched_rt_entity *rt_se = &p->rt;
+ struct rt_rq *rt_rq = &rq->rt;
+
+ if (on_rt_rq(&p->rt))
+ update_stats_wait_start_rt(rt_rq, rt_se);
+
update_curr_rt(rq);
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
We want to measure the latency of RT tasks in our production environment with schedstats facility, but currently schedstats is only supported for fair sched class. This patch enable it for RT sched class as well. After we make the struct sched_statistics and the helpers of it independent of fair sched class, we can easily use the schedstats facility for RT sched class. The schedstat usage in RT sched class is similar with fair sched class, for example, fair RT enqueue update_stats_enqueue_fair update_stats_enqueue_rt dequeue update_stats_dequeue_fair update_stats_dequeue_rt put_prev_task update_stats_wait_start update_stats_wait_start_rt set_next_task update_stats_wait_end update_stats_wait_end_rt The user can get the schedstats information in the same way in fair sched class. For example, fair RT /proc/[pid]/sched /proc/[pid]/sched The output of a RT task's schedstats as follows, $ cat /proc/227408/sched ... se.statistics.sum_sleep_runtime : 402284.476088 se.statistics.sum_block_runtime : 402272.475254 se.statistics.wait_start : 0.000000 se.statistics.sleep_start : 0.000000 se.statistics.block_start : 46903176.965093 se.statistics.sleep_max : 12.000834 se.statistics.block_max : 1446.963040 se.statistics.exec_max : 0.463806 se.statistics.slice_max : 0.000000 se.statistics.wait_max : 146.656326 se.statistics.wait_sum : 81741.944704 se.statistics.wait_count : 1004 se.statistics.iowait_sum : 77875.399958 se.statistics.iowait_count : 142 se.statistics.nr_migrations_cold : 0 se.statistics.nr_failed_migrations_affine : 0 se.statistics.nr_failed_migrations_running : 0 se.statistics.nr_failed_migrations_hot : 0 se.statistics.nr_forced_migrations : 0 se.statistics.nr_wakeups : 1003 se.statistics.nr_wakeups_sync : 0 se.statistics.nr_wakeups_migrate : 0 se.statistics.nr_wakeups_local : 351 se.statistics.nr_wakeups_remote : 652 se.statistics.nr_wakeups_affine : 0 se.statistics.nr_wakeups_affine_attempts : 0 se.statistics.nr_wakeups_passive : 0 se.statistics.nr_wakeups_idle : 0 ... The sched:sched_stat_{wait, sleep, iowait, blocked} tracepoints can be used to trace RT tasks as well. The output of these tracepoints for a RT tasks as follows, - blocked kworker/u113:0-230817 [000] d... 47197.452940: sched_stat_blocked: comm=stress pid=227408 delay=4096 [ns] - iowait kworker/3:1-222921 [003] d... 47492.211521: sched_stat_iowait: comm=stress pid=227408 delay=905187613 [ns] - wait stress-227400 [003] d... 47202.283021: sched_stat_wait: comm=stress pid=227408 delay=67958890 [ns] - runtime stress-227408 [003] d... 47202.283027: sched_stat_runtime: comm=stress pid=227408 runtime=7815 [ns] vruntime=0 [ns] - sleep sleep-244868 [022] dN.. 50070.614833: sched_stat_sleep: comm=sleep.sh pid=244300 delay=1001131165 [ns] sleep-244869 [022] dN.. 50071.616222: sched_stat_sleep: comm=sleep.sh pid=244300 delay=1001100486 [ns] sleep-244879 [022] dN.. 50072.617628: sched_stat_sleep: comm=sleep.sh pid=244300 delay=1001137198 [ns] [ In sleep.sh, it sleeps 1 sec each time. ] [lkp@intel.com: reported build failure in earlier version] Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Cc: kernel test robot <lkp@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alison Chaiken <achaiken@aurora.tech> --- kernel/sched/rt.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+)