Messages in this thread | | | Date | Thu, 14 Jun 2012 08:45:56 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [RFC patch 2/5] smpboot: Provide infrastructure for percpu hotplug threads |
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On Thu, Jun 14, 2012 at 04:56:29PM +0200, Peter Zijlstra wrote: > On Thu, 2012-06-14 at 07:47 -0700, Paul E. McKenney wrote: > > RCU callback processing consumes the entire CPU in RCU_BOOST case where > > processing runs at real-time priority. This is analogous to RT throttling > > in the scheduler. > > But previously we can in non-preemptible softirq context, why would if > behave differently when done from a RT task?
In -rt, yes, but in mainline, ksoftirqd does not run at RT prio, right?
> Also, no its not quite like the throttling, that really idles the cpu > even if there's no SCHED_OTHER tasks to run.
Agreed, not -exactly- like throttling, but it has a broadly similar goal, namely to prevent a given type of processing from starving everything else in the system.
That said, why does throttling idle the CPU even if there is no other SCHED_OTHER tasks to run?
Thanx, Paul
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