Messages in this thread | | | Date | Tue, 22 Feb 2011 09:43:33 +0530 | From | Bharata B Rao <> | Subject | Re: [CFS Bandwidth Control v4 5/7] sched: add exports tracking cfs bandwidth control statistics |
| |
On Tue, Feb 22, 2011 at 08:44:20AM +0530, Balbir Singh wrote: > * 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.
Given that cpuacct controller can be mounted independently, I am not sure if we should integrate these stats. These stats come from cpu controller.
I initially had similar stats as part of /proc/sched_debug since there are a bunch of other group specific stats (including rt throttle stats) in /proc/sched_debug.
Regards, Bharata.
| |