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items: Re: A question about group CFS scheduling

Re: A question about group CFS scheduling
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description: On Thu, 2008-06-26 at 16:33 +0800, Zhao Forrest wrote: > > > > Let me explain the cgroup case (the sanest option IMHO): > > > > initially all your tasks will belong to the root cgroup, eg: > > > > assuming: > > mkdir -p /cgroup/cpu > > mount none /cgroup/cpu -t cgroup -o cpu > > > > Then the root cgroup (cgroup:/) is /cgroup/cpu/ and all tasks will be > > found in /cgroup/cpu/tasks. > > > > You can then create new groups as sibling from this root group, eg: > > > > cgroup:/foo > > cgroup:/bar > > > > They will get a weigth of 1024 by default, exactly as heavy as a nice 0 > > task. > > > > That means that no matter how many tasks you stuff into foo, their > > combined cpu time will be as much as a single tasks in cgroup:/ would > > get. > > > > This is fully recursive, so you can also create: > > > > cgroup:/foo/bar and its tasks in turn will get as much combined cpu time > > as a single task in cgroup:/foo would get. > > > > In theory this should go on indefinitely, in practise we'll run into > > serious numerical issues quite quickly. > > > > > > The USER grouping basically creates a fake root and all uids (including > > 0) are its siblings. The only special case is that uid-0 (aka root) will > > get twice the weight of the others. > > > > Thank you for your detailed explanation! I have one more question: > cgrouping and USER grouping is mutual exclusive, am I right? That is, > when enabling cgrouping, USER grouping need to be disabled, vice > versa. Yes indeed. That is set at kernel build time. So the kernel either supports cgroup scheduling or uid stuff. _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/containers
creator: Peter Zijlstra
date: 2008-06-26T11:08:27-00:00