Messages in this thread | | | Subject | Re: [PATCH] sched: balance_cpu to consider other cpus in its group as target of (pinned) task migration | From | Mike Galbraith <> | Date | Mon, 04 Jun 2012 16:41:35 +0200 |
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On Mon, 2012-06-04 at 20:08 +0530, Srivatsa Vaddagiri wrote: > * Mike Galbraith <efault@gmx.de> [2012-06-04 16:30:34]: > > > Yeah, this is true, it is a latency source and a fairness violation. > > Slow path balance consideration does make some sense to me. > > > > But, if you have an RT requirement, you can't afford to mix unknown > > entities, nor over-commit etc. A realtime application will assign all > > resources, so the load balancer becomes essentially unemployed. No? > > Non critical worker-bees may be allowed to bounce around in say a > > cpuset, but none of the CPUs which do critical work will ever be > > over-committed, else application just lost the war. In that regard, > > twiddling the load balancer to accommodate strange sounding case still > > seems wrong to me. > > Btw the patch should help non-rt case as well (where a high > priority SCHED_OTHER is hogging cpu while low-priority SCHED_OTHER task > on that same cpu suffers as we choose not to move it to another > cpu (because of the way balance_cpu based load balance is written).
But high priority SCHED_OTHER tasks do not hog the CPU, they get their fair share as defined by the user.
-Mike
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