Messages in this thread | | | Subject | Re: [PATCH v4] cpuset: Enable cpuset controller in default hierarchy | From | Mike Galbraith <> | Date | Sat, 10 Mar 2018 04:47:28 +0100 |
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On Fri, 2018-03-09 at 18:06 -0500, Waiman Long wrote: > On 03/09/2018 05:17 PM, Peter Zijlstra wrote: > > On Fri, Mar 09, 2018 at 03:43:34PM -0500, Waiman Long wrote: > >> The isolcpus= parameter just reduce the cpus available to the rests of > >> the system. The cpuset controller does look at that value and make > >> adjustment accordingly, but it has no dependence on exclusive cpu/mem > >> features of cpuset. > > The isolcpus= boot param is donkey shit and needs to die. cpuset _used_ > > to be able to fully replace it, but with the advent of cgroup 'feature' > > this got lost. > > > > And instead of fixing it, you're making it _far_ worse. You completely > > removed all the bits that allow repartitioning the scheduler domains. > > > > Mike is completely right, full NAK on any such approach. > > So you are talking about sched_relax_domain_level and > sched_load_balance. I have not removed any bits. I just haven't exposed > them yet. It does seem like these 2 control knobs are useful from the > scheduling perspective. Do we also need cpu_exclusive or just the two > sched control knobs are enough?
Some form of cpu_exclusive (preferably exactly that, but something else could replace it) is needed to define sets that must not overlap any other set at creation time or any time thereafter. A set with property 'exclusive' is the enabler for fundamentally exclusive (but dynamic!) set properties such as 'isolated' (etc etc).
-Mike
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