Messages in this thread | | | Date | Wed, 23 Dec 2009 09:31:08 +0100 | Subject | Re: workqueue thing | From | Stijn Devriendt <> |
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On Tue, Dec 22, 2009 at 12:50 AM, Tejun Heo <tj@kernel.org> wrote: >> 2) doesn't deal with cpu heavy tasks/wakeup parallelism > > workqueue was never suited for this. MT workqueues have strong CPU > affinity which doesn't make sense for CPU-heavy workloads.
It does, really. Have a look at TBB and others. You always want to keep workqueue items as close to the scheduling thread as possible as the chance of having a hot cache and TLBs and such are far greater. The end result is CPU-affine threads fetching work from CPU-affine queues with workitems scheduled by a thread on that CPU. To improve parallellism, workqueue threads with empty workqueues start stealing work away from non-empty workqueues. The added warmup doesn't weigh in against the added parallellism in those cases.
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