Re: [RFC] perf_events: support for uncore a.k.a. nest units

From: stephane eranian
Date: Thu Jan 21 2010 - 03:47:51 EST

On Wed, Jan 20, 2010 at 10:33 PM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Wed, 2010-01-20 at 14:34 +0100, Peter Zijlstra wrote:
>> So how about PERF_TYPE_{CORE,NODE,SOCKET} like things?
> OK, so I read most of the intel uncore stuff, and it seems to suggest
> you need a regular pmu event to receive uncore events (chained setup),
> this seems rather retarded since it wastes a perfectly good pmu event
> and makes configuring all this more intricate...
I don't think that is correct. You can be using the uncore PMU on Nehalem
without any core PMU event. The only thing to realize is that uncore PMU
shares the same interrupt vector as core PMU. You need to configure which
core the uncore is going to interrupt on. This is done via a bitmask, so you
can interrupt more than one core at a time. Several strategies are possible.

> A well, nothing to be done about that I guess..
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