Messages in this thread | | | Date | Thu, 30 Jun 2011 21:13:12 +0800 | Subject | Re: [RFC] sched: check RT runqueue overloaded in tick timer | From | Hillf Danton <> |
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On Thu, Jun 30, 2011 at 8:55 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > On Thu, 2011-06-30 at 20:47 +0800, Hillf Danton wrote: >> Hi Steven >> >> When tick timer runs, runqueue overload is checked. If overloaded and other >> CPUs available at the moment, reschedule is fired to allow push logic to move >> the pushable tasks somewhere else. > > Why? > > This would be a waste of overhead. We check when a task is queued and > dequeue, and when a cpu lowers its priority (for a pull). There's no > need to randomly check if we need to push or pull based on timers. > That's just going to slow things down. > Got it.
If puller is inactive, there is no CPU available for the pushable.
Thanks Hillf
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