Messages in this thread | | | Date | Wed, 13 Jan 2010 17:35:51 +0100 | From | Ingo Molnar <> | Subject | Re: introduce NMI_AUTO as nmi_watchdog option |
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* Peter Zijlstra <peterz@infradead.org> wrote:
> On Wed, 2010-01-13 at 10:32 +0100, Ingo Molnar wrote: > > other architectures have NMI concepts as well, such as Sparc64. > > I think both sparc64 and ppc64 fake NMIs by playing games with hw IRQ > priorities and partial masks. But yes. > > One interesting 'feature' for the perf-nmi interaction is creating an idle > scheduling class for counters, because as long as there is a counter present > you can use his NMIs to drive the watchdog, but as soon as there are non > left, you need to install one.
Yeah. I'd suggest to not complicate things with that initially - but to simply create a standalone event for it and 'waste' a counter on NMI generation.
Later on it can indeed be a good feature to make the NMI watchdog 'seemless' in the sense of it not causing any wasted hw resources - it can piggyback on any existing NMI event. (as long as that event is at least ~1 HZ strong or so)
Ingo
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