Messages in this thread | | | Date | Tue, 2 Aug 2005 11:27:17 +0200 | From | Ingo Molnar <> | Subject | Re: [Patch] don't kick ALB in the presence of pinned task |
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* Siddha, Suresh B <suresh.b.siddha@intel.com> 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. > > Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
nice catch!
fine for -mm, but i dont think we need this fix in 2.6.13, as the effect of the bug is an extra context-switch per 'CPU goes idle' event, in this very specific (and arguably broken) task binding scenario. In a worst-case scenario a CPU going idle can 'spam' that other CPU with migration requests, but it still seems like a pretty artificial workload scenario where the system has significant idle time left. I have tested your fix on a HT box and it solves the problem.
Acked-by: Ingo Molnar <mingo@elte.hu>
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