Messages in this thread | | | Date | Tue, 23 Nov 2010 11:00:46 +0100 | Subject | Re: [RFC PATCH 2/3 v2] perf: Implement Nehalem uncore pmu | From | Stephane Eranian <> |
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On Sun, Nov 21, 2010 at 6:44 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > On Sun, 2010-11-21 at 22:04 +0800, Lin Ming wrote: >> On Sun, 2010-11-21 at 20:46 +0800, Andi Kleen wrote: >> > > >> > > 2. Uncore pmu NMI handling >> > > >> > > All the 4 cores are programmed to receive uncore counter overflow >> > > interrupt. The NMI handler(running on 1 of the 4 cores) handle all >> > > counters enabled by all 4 cores. >> > >> > Really for uncore monitoring there is no need to use an NMI handler. >> > You can't profile a core anyways, so you can just delay the reporting >> > a little bit. It may simplify the code to not use one here >> > and just use an ordinary handler. >> >> OK, I can use on ordinary interrupt handler here. > > Does the hardware actually allow using a different interrupt source? > It does not. It's using whatever you've programmed into the APIC LVT vector, AFAIK. Uncore interrupt mode is enabled via IA32_DEBUGCTL. Regarless of sampling or not, you need the interrupt to virtualize the counters to 64 bits.
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