Messages in this thread |  | | Date | Mon, 23 Feb 2009 16:55:17 +0530 | | From | Balbir Singh <> | | Subject | Re: [RFC PATCH 0/4] timers: framework for migration between CPU |
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* Ingo Molnar <mingo@elte.hu> [2009-02-23 12:07:25]:
> > * Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote: > > > My understanding is that we will certainly have a sysfs > > tunable to 'enable' timer migration or consolidation, similar > > to the sched_mc=2 policy, but the actual set of CPUs to > > evacuate and the correct set of target CPUs to consolidate > > should come from the scheduler and not necessarily from the > > user space. > > Yes. > > > The scheduler should be able to figure out the following > > parameters: > > > > * Identify set of idle CPUs (CPU package) from which timers > > can be removed > > * Identify a semi-idle or idle CPU package to which the timers > > can be moved > > * Decide when to start moving timers as the system has large > > number of idle CPUs > > * Decide when to stop migrating as system becomes less idle > > and utilisation increases > > > > Guiding all of the above decisions from user space may not be > > fast enough. > > Exactly. >
OK, lets head that way for now. I've highlighted my concerns in a different email. Experimentation will definitely show us if they are justified or not.
-- Balbir
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