Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 22 Nov 2010 11:52:42 +0530 | From | Balbir Singh <> | Subject | Re: [RFC/RFT PATCH v3] sched: automated per tty task groups |
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* Peter Zijlstra <a.p.zijlstra@chello.nl> [2010-11-19 12:49:36]:
> On Fri, 2010-11-19 at 00:43 +0100, Samuel Thibault wrote: > > What overhead? The implementation of cgroups is actually already > > hierarchical. > > It must be nice to be that ignorant ;-) Speaking for the scheduler > cgroup controller (that being the only one I actually know), most all > the load-balance operations are O(n) in the number of active cgroups, > and a lot of the cpu local schedule operations are O(d) where d is the > depth of the cgroup tree. > > [ and that's with the .38 targeted code, current mainline is O(n ln(n)) > for load balancing and truly sucks on multi-socket ] >
I can say that for memory, with hierarchies we account all the way up, which can be a visible overhead, depending on how often you fault.
-- Three Cheers, Balbir
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