Messages in this thread | | | Subject | Re: [PATCH] Extend mwait idle to optimize away CAL and RES interrupts to an idle CPU -v1 | From | Peter Zijlstra <> | Date | Mon, 27 Feb 2012 10:30:58 +0100 |
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On Mon, 2012-02-27 at 17:08 +0800, Yong Zhang wrote: > On Mon, Feb 27, 2012 at 09:38:01AM +0100, Peter Zijlstra wrote: > > On Fri, 2012-02-24 at 14:13 +0800, Yong Zhang wrote: > > > > > This remind me that we should have moved the irq_enter()/irq_exit() to > > > each arch's related irq handler. > > > see: http://marc.info/?l=linux-kernel&m=130709505700821&w=2 > > > > > > So Peter, is there someone alread on it? or it still worth doing now? > > > > trouble was that some people didn't feel comfortable adding that > > overhead to plain resched IPIs that didn't need to do anything. > > Any ideas on where the plain resched IPIs come from?
remote wakeups that don't queue I guess.
IIRC I looked at it a while back and while not in the majority there were still a few (I only added counters, didn't look where they came from).
However since 518cd623 there'd be a lot more I guess..
Feel free to investigate. Also, some non-sched users of the resched ipi exist, eg. KVM uses it to kick a remote vcpu out from guest mode.
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