Messages in this thread | | | Date | Fri, 26 Nov 2010 12:25:51 +0100 | Subject | Re: [RFC PATCH 2/3 v2] perf: Implement Nehalem uncore pmu | From | Stephane Eranian <> |
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On Fri, Nov 26, 2010 at 12:24 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > On Fri, 2010-11-26 at 09:18 +0100, Stephane Eranian wrote: > >> In the perf_event model, given that any one of the 4 cores can be used >> to program uncore events, you have no choice but to broadcast to all >> 4 cores. Each has to demultiplex and figure out which of its counters >> have overflowed. > > Not really, you can redirect all these events to the first online cpu of > the node. > > You can re-write event->cpu in pmu::event_init(), and register cpu > hotplug notifiers to migrate the state around. > I am sure you could. But then the user thinks the event is controlled from CPUx when it's actually from CPUz. I am sure it can work but that's confusing, especially interrupt-wise.
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