Re: [PATCH] sched: balance_cpu to consider other cpus in its groupas target of (pinned) task migration
From: Srivatsa Vaddagiri
Date: Mon Jun 04 2012 - 10:38:08 EST
* Mike Galbraith <efault@xxxxxx> [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).
- vatsa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/