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    SubjectRe: [PATCH] perf, x86: catch spurious interrupts after disabling counters
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    On Fri, 2010-09-24 at 15:38 +0200, Stephane Eranian wrote:
    > > I don't like the approach of disabling all counters in the nmi
    > > handler. First, it stops counting and thus may falsify
    > > measurement. Second, it introduces much overhead doing a rd-/wrmsrl()
    > > for each counter.
    > >
    > But that's exactly what is going on the Intel side. PMU is stopped on interrupt.
    > An argument for this is that you don't necessarily want to monitor across
    > the PMU handler, i.e., the overhead you introduce.

    Right, its really a question of what you want to measure. I prefer not
    to measure the measuring itself, things are hard enough to interpret
    already.

    Then again, the Intel stuff has a real handy way to disable the whole
    PMU, unlike the AMD bits where you need to iterate each counter
    individually.
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