Messages in this thread | | | Date | Tue, 7 Jul 2015 16:20:01 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 5/8] nohz: Restart the tick from irq exit |
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On Sun, Jun 14, 2015 at 02:49:16PM +0530, Preeti U Murthy wrote: > On 06/11/2015 11:06 PM, Frederic Weisbecker wrote: > > Restart the tick when necessary from the irq exit path. It makes nohz > > full more flexible and allow it to piggyback the tick restart on the > > scheduler IPI in the future instead of sending a dedicated IPI that > > often doubles the scheduler IPI on task wakeup. This will require > > You can piggy back on the scheduler ipi when you add a timer/hrtimer and > add a new task to the runqueue of the nohz_full cpus, since we call > resched_curr() in these code paths. But what about the calls to kick > nohz_full cpus by perf events and posix cpu timers ? These call sites > seem to be concerned about specifically waking up nohz_full cpus as far > as I can see. IOW there is no scheduling ipi that we can fall back on in > these paths.
Sure, those will need to keep the current IPI. They are less of a worry because they should be rare events compared to the scheduler.
Thanks.
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