Messages in this thread | | | Date | Tue, 1 May 2018 09:11:12 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sched/fair: make CFS bandwidth slice per cpu group |
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On Mon, Apr 30, 2018 at 01:37:16PM -0700, Cong Wang wrote: > On Mon, Apr 30, 2018 at 12:42 PM, Peter Zijlstra <peterz@infradead.org> wrote: > > On Mon, Apr 30, 2018 at 12:29:25PM -0700, Cong Wang wrote: > >> Currently, the sched_cfs_bandwidth_slice_us is a global setting which > >> affects all cgroups. Different groups may want different values based > >> on their own workload, one size doesn't fit all. The global pool filled > >> periodically is per cgroup too, they should have the right to distribute > >> their own quota to each local CPU with their own frequency. > > > > Why.. what happens? This doesn't really tell us anything. > > We saw tasks in a container got throttled for many times even > when they don't apparently over-burn the CPU's. I tried to reduce > the sched_cfs_bandwidth_slice_us from the default 5ms to 1ms, > it solved the problem as no tasks got throttled after this change. > This is why I want to change it.
The 1ms slice distributes time better at the cost of higher overhead, right?
> And I don't think 1ms will be good for all containers, so in order to > minimize the impact, I would like to keep the slice change within > each container. This is why I propose this patch rather just > `sysctl -w`. Do you think otherwise?
Well, I think I don't quite remember everything and a Changelog that tells me why you want stuff in a little more detail and helps me remember some things is a lot more useful than me having to go dig through the code myself (which I'll invariably postpone because I'm a busy sort of person).
> BTW, people reported a similar (if not same) issue here before: > https://gist.github.com/bobrik/2030ff040fad360327a5fab7a09c4ff1
That's not a report, that's a random person on the interweb posting random crap. A report lands in my inbox.
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