lkml.org 
[lkml]   [2010]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [RFC PATCH 2/3 v2] perf: Implement Nehalem uncore pmu
    From
    Date
    On Fri, 2010-11-26 at 19:36 +0800, Peter Zijlstra wrote:
    > On Fri, 2010-11-26 at 12:25 +0100, Stephane Eranian wrote:
    > > 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.
    >
    > Well, its either that or keeping a node wide state like we do for AMD
    > and serialize everything from there.
    >
    > And I'm not sure what's most expensive, steering the interrupt to one
    > core only, or broadcasting every interrupt, I'd favour the first
    > approach.
    >
    > The whole thing is a node-wide resource, so the user needs to think in
    > nodes anyway, we already do a cpu->node mapping for identifying the
    > thing.

    How about a new sub-command for node-wide events statistics?

    perf node -n <node> -e <event>?




    \
     
     \ /
      Last update: 2010-12-01 04:29    [W:0.022 / U:148.348 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site