From: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
To: Paul Turner <pjt@google.com>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Bharata B Rao <bharata@linux.vnet.ibm.com>,
Dhaval Giani <dhaval.giani@gmail.com>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
Ingo Molnar <mingo@elte.hu>, Pavel Emelyanov <xemul@openvz.org>
Subject: Re: [patch 14/15] sched: return unused runtime on voluntary sleep
Date: Tue, 10 May 2011 16:28:03 +0900 [thread overview]
Message-ID: <4DC8E903.9080002@jp.fujitsu.com> (raw)
In-Reply-To: <20110503092905.694819271@google.com>
(2011/05/03 18:29), Paul Turner wrote:
> When a local cfs_rq blocks we return the majority of its remaining quota to the
> global bandwidth pool for use by other runqueues.
>
> We do this only when the quota is current and there is more than
> min_cfs_rq_quota [1ms by default] of runtime remaining on the rq.
>
> In the case where there are throttled runqueues and we have sufficient
> bandwidth to meter out a slice, a second timer is kicked off to handle this
> delivery, unthrottling where appropriate.
>
> Using a 'worst case' antagonist which executes on each cpu
> for 1ms before moving onto the next on a fairly large machine:
>
> no quota generations:
> 197.47 ms /cgroup/a/cpuacct.usage
> 199.46 ms /cgroup/a/cpuacct.usage
> 205.46 ms /cgroup/a/cpuacct.usage
> 198.46 ms /cgroup/a/cpuacct.usage
> 208.39 ms /cgroup/a/cpuacct.usage
> Since we are allowed to use "stale" quota our usage is effectively bounded by
> the rate of input into the global pool and performance is relatively stable.
>
> with quota generations [1s increments]:
> 119.58 ms /cgroup/a/cpuacct.usage
> 119.65 ms /cgroup/a/cpuacct.usage
> 119.64 ms /cgroup/a/cpuacct.usage
> 119.63 ms /cgroup/a/cpuacct.usage
> 119.60 ms /cgroup/a/cpuacct.usage
> The large deficit here is due to quota generations (/intentionally/) preventing
> us from now using previously stranded slack quota. The cost is that this quota
> becomes unavailable.
>
> with quota generations and quota return:
> 200.09 ms /cgroup/a/cpuacct.usage
> 200.09 ms /cgroup/a/cpuacct.usage
> 198.09 ms /cgroup/a/cpuacct.usage
> 200.09 ms /cgroup/a/cpuacct.usage
> 200.06 ms /cgroup/a/cpuacct.usage
> By returning unused quota we're able to both stably consume our desired quota
> and prevent unintentional overages due to the abuse of slack quota from
> previous quota periods (especially on a large machine).
>
> Signed-off-by: Paul Turner <pjt@google.com>
>
> ---
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Thanks,
H.Seto
next prev parent reply other threads:[~2011-05-10 7:28 UTC|newest]
Thread overview: 129+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-03 9:28 [patch 00/15] CFS Bandwidth Control V6 Paul Turner
2011-05-03 9:28 ` [patch 01/15] sched: (fixlet) dont update shares twice on on_rq parent Paul Turner
2011-05-10 7:14 ` Hidetoshi Seto
2011-05-10 8:32 ` Mike Galbraith
2011-05-11 7:55 ` Hidetoshi Seto
2011-05-11 8:13 ` Paul Turner
2011-05-11 8:45 ` Mike Galbraith
2011-05-11 8:59 ` Hidetoshi Seto
2011-05-03 9:28 ` [patch 02/15] sched: hierarchical task accounting for SCHED_OTHER Paul Turner
2011-05-10 7:17 ` Hidetoshi Seto
2011-05-03 9:28 ` [patch 03/15] sched: introduce primitives to account for CFS bandwidth tracking Paul Turner
2011-05-10 7:18 ` Hidetoshi Seto
2011-05-03 9:28 ` [patch 04/15] sched: validate CFS quota hierarchies Paul Turner
2011-05-10 7:20 ` Hidetoshi Seto
2011-05-11 9:37 ` Paul Turner
2011-05-16 9:30 ` Peter Zijlstra
2011-05-16 9:43 ` Peter Zijlstra
2011-05-16 12:32 ` Paul Turner
2011-05-17 15:26 ` Peter Zijlstra
2011-05-18 7:16 ` Paul Turner
2011-05-18 11:57 ` Peter Zijlstra
2011-05-03 9:28 ` [patch 05/15] sched: add a timer to handle CFS bandwidth refresh Paul Turner
2011-05-10 7:21 ` Hidetoshi Seto
2011-05-11 9:27 ` Paul Turner
2011-05-16 10:18 ` Peter Zijlstra
2011-05-16 12:56 ` Paul Turner
2011-05-03 9:28 ` [patch 06/15] sched: accumulate per-cfs_rq cpu usage and charge against bandwidth Paul Turner
2011-05-10 7:22 ` Hidetoshi Seto
2011-05-11 9:25 ` Paul Turner
2011-05-16 10:27 ` Peter Zijlstra
2011-05-16 12:59 ` Paul Turner
2011-05-17 15:28 ` Peter Zijlstra
2011-05-18 7:02 ` Paul Turner
2011-05-16 10:32 ` Peter Zijlstra
2011-05-03 9:28 ` [patch 07/15] sched: expire invalid runtime Paul Turner
2011-05-10 7:22 ` Hidetoshi Seto
2011-05-16 11:05 ` Peter Zijlstra
2011-05-16 11:07 ` Peter Zijlstra
2011-05-03 9:28 ` [patch 08/15] sched: throttle cfs_rq entities which exceed their local runtime Paul Turner
2011-05-10 7:23 ` Hidetoshi Seto
2011-05-16 15:58 ` Peter Zijlstra
2011-05-16 16:05 ` Peter Zijlstra
2011-05-03 9:28 ` [patch 09/15] sched: unthrottle cfs_rq(s) who ran out of quota at period refresh Paul Turner
2011-05-10 7:24 ` Hidetoshi Seto
2011-05-11 9:24 ` Paul Turner
2011-05-03 9:28 ` [patch 10/15] sched: allow for positional tg_tree walks Paul Turner
2011-05-10 7:24 ` Hidetoshi Seto
2011-05-17 13:31 ` Peter Zijlstra
2011-05-18 7:18 ` Paul Turner
2011-05-03 9:28 ` [patch 11/15] sched: prevent interactions between throttled entities and load-balance Paul Turner
2011-05-10 7:26 ` Hidetoshi Seto
2011-05-11 9:11 ` Paul Turner
2011-05-03 9:28 ` [patch 12/15] sched: migrate throttled tasks on HOTPLUG Paul Turner
2011-05-10 7:27 ` Hidetoshi Seto
2011-05-11 9:10 ` Paul Turner
2011-05-03 9:28 ` [patch 13/15] sched: add exports tracking cfs bandwidth control statistics Paul Turner
2011-05-10 7:27 ` Hidetoshi Seto
2011-05-11 7:56 ` Hidetoshi Seto
2011-05-11 9:09 ` Paul Turner
2011-05-03 9:29 ` [patch 14/15] sched: return unused runtime on voluntary sleep Paul Turner
2011-05-10 7:28 ` Hidetoshi Seto [this message]
2011-05-03 9:29 ` [patch 15/15] sched: add documentation for bandwidth control Paul Turner
2011-05-10 7:29 ` Hidetoshi Seto
2011-05-11 9:09 ` Paul Turner
2011-06-07 15:45 ` CFS Bandwidth Control - Test results of cgroups tasks pinned vs unpinned Kamalesh Babulal
2011-06-08 3:09 ` Paul Turner
2011-06-08 10:46 ` Vladimir Davydov
2011-06-08 16:32 ` Kamalesh Babulal
2011-06-09 3:25 ` Paul Turner
2011-06-10 18:17 ` Kamalesh Babulal
2011-06-14 0:00 ` Paul Turner
2011-06-15 5:37 ` Kamalesh Babulal
2011-06-21 19:48 ` Paul Turner
2011-06-24 15:05 ` Kamalesh Babulal
2011-09-07 11:00 ` Srivatsa Vaddagiri
2011-09-07 14:54 ` Srivatsa Vaddagiri
2011-09-07 15:20 ` CFS Bandwidth Control - Test results of cgroups tasks pinned vs unpinnede Srivatsa Vaddagiri
2011-09-07 19:22 ` Peter Zijlstra
2011-09-08 15:15 ` Srivatsa Vaddagiri
2011-09-09 12:31 ` Peter Zijlstra
2011-09-09 13:26 ` Srivatsa Vaddagiri
2011-09-12 10:17 ` Srivatsa Vaddagiri
2011-09-12 12:35 ` Peter Zijlstra
2011-09-13 4:15 ` Srivatsa Vaddagiri
2011-09-13 5:03 ` Srivatsa Vaddagiri
2011-09-13 5:05 ` Srivatsa Vaddagiri
2011-09-13 9:39 ` Peter Zijlstra
2011-09-13 11:28 ` Srivatsa Vaddagiri
2011-09-13 14:07 ` Peter Zijlstra
2011-09-13 16:21 ` Srivatsa Vaddagiri
2011-09-13 16:33 ` Peter Zijlstra
2011-09-13 17:41 ` Srivatsa Vaddagiri
2011-09-13 16:36 ` Peter Zijlstra
2011-09-13 17:54 ` Srivatsa Vaddagiri
2011-09-13 18:03 ` Peter Zijlstra
2011-09-13 18:12 ` Srivatsa Vaddagiri
2011-09-13 18:07 ` Peter Zijlstra
2011-09-13 18:19 ` Peter Zijlstra
2011-09-13 18:28 ` Srivatsa Vaddagiri
2011-09-13 18:30 ` Peter Zijlstra
2011-09-13 18:35 ` Srivatsa Vaddagiri
2011-09-15 17:55 ` Kamalesh Babulal
2011-09-15 21:48 ` Peter Zijlstra
2011-09-19 17:51 ` Kamalesh Babulal
2011-09-20 0:38 ` Venki Pallipadi
2011-09-20 11:09 ` Kamalesh Babulal
2011-09-20 13:56 ` Peter Zijlstra
2011-09-20 14:04 ` Peter Zijlstra
2011-09-20 12:55 ` Peter Zijlstra
2011-09-21 17:34 ` Kamalesh Babulal
2011-09-13 14:19 ` Peter Zijlstra
2011-09-13 18:01 ` Srivatsa Vaddagiri
2011-09-13 18:23 ` Peter Zijlstra
2011-09-16 8:14 ` Paul Turner
2011-09-16 8:28 ` Peter Zijlstra
2011-09-19 16:35 ` Srivatsa Vaddagiri
2011-09-16 8:22 ` Paul Turner
2011-06-14 10:16 ` CFS Bandwidth Control - Test results of cgroups tasks pinned vs unpinned Hidetoshi Seto
2011-06-14 6:58 ` [patch 00/15] CFS Bandwidth Control V6 Hu Tao
2011-06-14 7:29 ` Hidetoshi Seto
2011-06-14 7:44 ` Hu Tao
2011-06-15 8:37 ` Hu Tao
2011-06-16 0:57 ` Hidetoshi Seto
2011-06-16 9:45 ` Hu Tao
2011-06-17 1:22 ` Hidetoshi Seto
2011-06-17 6:05 ` Hu Tao
2011-06-17 6:25 ` Paul Turner
2011-06-17 9:13 ` Hidetoshi Seto
2011-06-18 0:28 ` Paul Turner
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