Messages in this thread | | | Date | Thu, 12 May 2005 09:16:37 -0700 | From | Tony Lindgren <> | Subject | Re: [RFC] (How to) Let idle CPUs sleep |
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* Lee Revell <rlrevell@joe-job.com> [050512 09:05]: > On Thu, 2005-05-12 at 14:16 +0530, Srivatsa Vaddagiri wrote: > > On Wed, May 11, 2005 at 11:03:49AM -0700, Tony Lindgren wrote: > > > Sorry to jump in late. For embedded stuff we should be able to skip > > > ticks until something _really_ happens, like an interrupt. > > > > > > So we need to be able to skip ticks several seconds at a time. Ticks > > > should be event driven. For embedded systems option B is really > > > the only way to go to take advantage of the power savings. > > > > I don't know how sensitive embedded platforms are to load imbalance. > > If they are not sensitive, then we could let the max time idle > > cpus are allowed to sleep to be few seconds. That way, idle CPU > > wakes up once in 3 or 4 seconds to check for imbalance and still > > be able to save power for those 3/4 seconds that it sleeps. > > Not very. Embedded systems are usually UP so don't care at all. If an > embedded system is SMP often it's because one CPU is dedicated to RT > tasks, and this model will become less common as RT preemption allows > you to do everything on a single processor.
Yes UP mostly & sounds like this only affects MP systems.
Although there is ARM MP support patches available. I guess embedded MP systems may be used for multimedia stuff eventually.
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