Messages in this thread Patch in this message | | | Date | Thu, 21 Jul 2011 09:43:40 -0700 | From | Paul Turner <> | Subject | [patch 15/18] sched: add exports tracking cfs bandwidth control statistics |
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From: Nikhil Rao <ncrao@google.com>
This change introduces statistics exports for the cpu sub-system, these are added through the use of a stat file similar to that exported by other subsystems.
The following exports are included:
nr_periods: number of periods in which execution occurred nr_throttled: the number of periods above in which execution was throttle throttled_time: cumulative wall-time that any cpus have been throttled for this group
Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Nikhil Rao <ncrao@google.com> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
--- kernel/sched.c | 21 +++++++++++++++++++++ kernel/sched_fair.c | 7 +++++++ 2 files changed, 28 insertions(+)
Index: tip/kernel/sched.c =================================================================== --- tip.orig/kernel/sched.c +++ tip/kernel/sched.c @@ -259,6 +259,9 @@ struct cfs_bandwidth { struct hrtimer period_timer; struct list_head throttled_cfs_rq; + /* statistics */ + int nr_periods, nr_throttled; + u64 throttled_time; #endif }; @@ -399,6 +402,7 @@ struct cfs_rq { u64 runtime_expires; s64 runtime_remaining; + u64 throttled_timestamp; int throttled, throttle_count; struct list_head throttled_list; #endif @@ -9213,6 +9217,19 @@ static int __cfs_schedulable(struct task return ret; } + +static int cpu_stats_show(struct cgroup *cgrp, struct cftype *cft, + struct cgroup_map_cb *cb) +{ + struct task_group *tg = cgroup_tg(cgrp); + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); + + cb->fill(cb, "nr_periods", cfs_b->nr_periods); + cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); + cb->fill(cb, "throttled_time", cfs_b->throttled_time); + + return 0; +} #endif /* CONFIG_CFS_BANDWIDTH */ #endif /* CONFIG_FAIR_GROUP_SCHED */ @@ -9259,6 +9276,10 @@ static struct cftype cpu_files[] = { .read_u64 = cpu_cfs_period_read_u64, .write_u64 = cpu_cfs_period_write_u64, }, + { + .name = "stat", + .read_map = cpu_stats_show, + }, #endif #ifdef CONFIG_RT_GROUP_SCHED { Index: tip/kernel/sched_fair.c =================================================================== --- tip.orig/kernel/sched_fair.c +++ tip/kernel/sched_fair.c @@ -1528,6 +1528,7 @@ static void throttle_cfs_rq(struct cfs_r rq->nr_running -= task_delta; cfs_rq->throttled = 1; + cfs_rq->throttled_timestamp = rq->clock; raw_spin_lock(&cfs_b->lock); list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq); raw_spin_unlock(&cfs_b->lock); @@ -1545,8 +1546,10 @@ static void unthrottle_cfs_rq(struct cfs cfs_rq->throttled = 0; raw_spin_lock(&cfs_b->lock); + cfs_b->throttled_time += rq->clock - cfs_rq->throttled_timestamp; list_del_rcu(&cfs_rq->throttled_list); raw_spin_unlock(&cfs_b->lock); + cfs_rq->throttled_timestamp = 0; update_rq_clock(rq); /* update hierarchical throttle state */ @@ -1634,6 +1637,7 @@ static int do_sched_cfs_period_timer(str throttled = !list_empty(&cfs_b->throttled_cfs_rq); /* idle depends on !throttled (for the case of a large deficit) */ idle = cfs_b->idle && !throttled; + cfs_b->nr_periods += overrun; /* if we're going inactive then everything else can be deferred */ if (idle) @@ -1647,6 +1651,9 @@ static int do_sched_cfs_period_timer(str goto out_unlock; } + /* account preceding periods in which throttling occurred */ + cfs_b->nr_throttled += overrun; + /* * There are throttled entities so we must first use the new bandwidth * to unthrottle them before making it generally available. This
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