Messages in this thread | | | From | Cong Wang <> | Date | Mon, 18 Jun 2018 21:36:49 -0700 | Subject | Re: [PATCH 2/2] sched/fair: Advance global expiration when period timer is restarted |
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On Mon, Jun 18, 2018 at 2:16 AM, Xunlei Pang <xlpang@linux.alibaba.com> wrote: > I noticed the group frequently got throttled even it consumed > low cpu usage, this caused some jitters on the response time > to some of our business containers enabling cpu quota. > > It's very easy to reproduce: > mkdir /sys/fs/cgroup/cpu/test > cd /sys/fs/cgroup/cpu/test > echo 100000 > cpu.cfs_quota_us > echo $$ > tasks > then repeat: > cat cpu.stat |grep nr_throttled // nr_throttled will increase > > After some analysis, we found that cfs_rq::runtime_remaining will > be cleared by expire_cfs_rq_runtime() due to two equal but stale > "cfs_{b|q}->runtime_expires" after period timer is re-armed. > > The global expiration should be advanced accordingly when the > bandwidth period timer is restarted. >
I observed the same problem and already sent some patches:
https://lkml.org/lkml/2018/5/22/37 https://lkml.org/lkml/2018/5/22/38 https://lkml.org/lkml/2018/5/22/35
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