Messages in this thread | | | Date | Thu, 2 Aug 2007 17:03:50 +0200 | From | Ingo Molnar <> | Subject | Re: Scheduling the highest priority task |
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* Martin Roehricht <ml@felicis.org> wrote:
> On 08/02/2007 01:40 PM, Ingo Molnar wrote: > >in the SMP migration code, the 'old scheduler' indeed picks the lowest > >priority one, _except_ if that task is running on another CPU or is too > >'cache hot': > > But why is it, that the scheduler picks the lowest priority one? I > thought sched_find_first_bit() picks the index of the lowest order bit > in the bitmap and thus the highest priority job. Is that wrong? What > needs to be changed to let the scheduler pick the highest priority > task from a given runqueue? I am very confused ...
it first picks the lowest index (i.e. the highest priority active priority-queue), but within those tasks (each task in that priority queue has equal priority) the load-balancer has freedom to pick any. Based on performance data we went for picking from the tail of the queue.
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