Messages in this thread | | | Date | Tue, 2 Aug 2005 11:43:18 +0200 | From | Ingo Molnar <> | Subject | Re: [Patch] don't kick ALB in the presence of pinned task |
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* Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> Siddha, Suresh B wrote: > >Jack Steiner brought this issue at my OLS talk. > > > >Take a scenario where two tasks are pinned to two HT threads in a physical > >package. Idle packages in the system will keep kicking migration_thread > >on the busy package with out any success. > > > >We will run into similar scenarios in the presence of CMP/NUMA. > > > >Patch appended. > > > > Hmm, I would have hoped the new "all_pinned" logic should have handled > this case properly. [...]
no, active_balance is a different case, not covered by the all_pinned logic. This is a HT-special scenario, where busiest->nr_running == 1, and we have to do active load-balancing. This does not go through move_tasks() and does not set all_pinned. (If nr_running werent 1 we'd not have to kick active load-balancing.)
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