Messages in this thread | | | Date | Tue, 22 Feb 2011 08:44:20 +0530 | From | Balbir Singh <> | Subject | Re: [CFS Bandwidth Control v4 5/7] sched: add exports tracking cfs bandwidth control statistics |
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* Paul Turner <pjt@google.com> [2011-02-15 19:18:36]:
> 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> > --- > kernel/sched.c | 26 ++++++++++++++++++++++++++ > kernel/sched_fair.c | 16 +++++++++++++++- > 2 files changed, 41 insertions(+), 1 deletion(-) > > Index: tip/kernel/sched.c > =================================================================== > --- tip.orig/kernel/sched.c > +++ tip/kernel/sched.c > @@ -254,6 +254,11 @@ struct cfs_bandwidth { > ktime_t period; > u64 runtime, quota; > struct hrtimer period_timer; > + > + /* throttle statistics */ > + u64 nr_periods; > + u64 nr_throttled; > + u64 throttled_time; > }; > #endif > > @@ -389,6 +394,7 @@ struct cfs_rq { > #ifdef CONFIG_CFS_BANDWIDTH > u64 quota_assigned, quota_used; > int throttled; > + u64 throttled_timestamp; > #endif > #endif > }; > @@ -426,6 +432,10 @@ void init_cfs_bandwidth(struct cfs_bandw > > hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); > cfs_b->period_timer.function = sched_cfs_period_timer; > + > + cfs_b->nr_periods = 0; > + cfs_b->nr_throttled = 0; > + cfs_b->throttled_time = 0; > } > > static > @@ -9332,6 +9342,18 @@ static int cpu_cfs_period_write_u64(stru > return tg_set_cfs_period(cgroup_tg(cgrp), cfs_period_us); > } > > +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 */ > > @@ -9378,6 +9400,10 @@ 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 > @@ -1519,17 +1519,25 @@ static void throttle_cfs_rq(struct cfs_r > > out_throttled: > cfs_rq->throttled = 1; > + cfs_rq->throttled_timestamp = rq_of(cfs_rq)->clock; > update_cfs_rq_load_contribution(cfs_rq, 1); > } > > static void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) > { > struct rq *rq = rq_of(cfs_rq); > + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); > struct sched_entity *se; > > se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; > > update_rq_clock(rq); > + /* update stats */ > + raw_spin_lock(&cfs_b->lock); > + cfs_b->throttled_time += (rq->clock - cfs_rq->throttled_timestamp); > + raw_spin_unlock(&cfs_b->lock); > + cfs_rq->throttled_timestamp = 0; > + > /* (Try to) avoid maintaining share statistics for idle time */ > cfs_rq->load_stamp = cfs_rq->load_last = rq->clock_task; > > @@ -1571,7 +1579,7 @@ static void account_cfs_rq_quota(struct > > static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) > { > - int i, idle = 1; > + int i, idle = 1, num_throttled = 0; > u64 delta; > const struct cpumask *span; > > @@ -1593,6 +1601,7 @@ static int do_sched_cfs_period_timer(str > > if (!cfs_rq_throttled(cfs_rq)) > continue; > + num_throttled++; > > delta = tg_request_cfs_quota(cfs_rq->tg); > > @@ -1608,6 +1617,11 @@ static int do_sched_cfs_period_timer(str > } > } > > + /* update throttled stats */ > + cfs_b->nr_periods++; > + if (num_throttled) > + cfs_b->nr_throttled++; > + > return idle; > } >
Should we consider integrating this in cpuacct, it would be difficult if we spill over stats between controllers.
-- Three Cheers, Balbir
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