sched/pelt: Add a new runnable average signal
Now that runnable_load_avg has been removed, we can replace it by a new
signal that will highlight the runnable pressure on a cfs_rq. This signal
track the waiting time of tasks on rq and can help to better define the
state of rqs.
At now, only util_avg is used to define the state of a rq:
A rq with more that around 80% of utilization and more than 1 tasks is
considered as overloaded.
But the util_avg signal of a rq can become temporaly low after that a task
migrated onto another rq which can bias the classification of the rq.
When tasks compete for the same rq, their runnable average signal will be
higher than util_avg as it will include the waiting time and we can use
this signal to better classify cfs_rqs.
The new runnable_avg will track the runnable time of a task which simply
adds the waiting time to the running time. The runnable _avg of cfs_rq
will be the /Sum of se's runnable_avg and the runnable_avg of group entity
will follow the one of the rq similarly to util_avg.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: "Dietmar Eggemann <dietmar.eggemann@arm.com>"
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Link: https://lore.kernel.org/r/20200224095223.13361-9-mgorman@techsingularity.net
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index cfecaad..8331bc0 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -405,6 +405,7 @@ static void print_cfs_group_stats(struct seq_file *m, int cpu, struct task_group
#ifdef CONFIG_SMP
P(se->avg.load_avg);
P(se->avg.util_avg);
+ P(se->avg.runnable_avg);
#endif
#undef PN_SCHEDSTAT
@@ -524,6 +525,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
#ifdef CONFIG_SMP
SEQ_printf(m, " .%-30s: %lu\n", "load_avg",
cfs_rq->avg.load_avg);
+ SEQ_printf(m, " .%-30s: %lu\n", "runnable_avg",
+ cfs_rq->avg.runnable_avg);
SEQ_printf(m, " .%-30s: %lu\n", "util_avg",
cfs_rq->avg.util_avg);
SEQ_printf(m, " .%-30s: %u\n", "util_est_enqueued",
@@ -532,8 +535,8 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
cfs_rq->removed.load_avg);
SEQ_printf(m, " .%-30s: %ld\n", "removed.util_avg",
cfs_rq->removed.util_avg);
- SEQ_printf(m, " .%-30s: %ld\n", "removed.runnable_sum",
- cfs_rq->removed.runnable_sum);
+ SEQ_printf(m, " .%-30s: %ld\n", "removed.runnable_avg",
+ cfs_rq->removed.runnable_avg);
#ifdef CONFIG_FAIR_GROUP_SCHED
SEQ_printf(m, " .%-30s: %lu\n", "tg_load_avg_contrib",
cfs_rq->tg_load_avg_contrib);
@@ -944,8 +947,10 @@ void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
P(se.load.weight);
#ifdef CONFIG_SMP
P(se.avg.load_sum);
+ P(se.avg.runnable_sum);
P(se.avg.util_sum);
P(se.avg.load_avg);
+ P(se.avg.runnable_avg);
P(se.avg.util_avg);
P(se.avg.last_update_time);
P(se.avg.util_est.ewma);
