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Date: Thu, 4 Aug 2016 17:00:38 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: David Carrillo-Cisneros <davidcc@google.com>
Cc: linux-kernel@vger.kernel.org, "x86@kernel.org" <x86@kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Thomas Gleixner <tglx@linutronix.de>,
        Andi Kleen <ak@linux.intel.com>, Kan Liang <kan.liang@intel.com>,
        Paul Turner <pjt@google.com>, Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 2/3] perf/core: introduce pmu_event_flags and
 PMUEF_READ_CPU_PKG
Message-ID: <20160804150038.GQ6862@twins.programming.kicks-ass.net>
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On Mon, Aug 01, 2016 at 07:44:54PM -0700, David Carrillo-Cisneros wrote:
> Introduce the flag PMUEF_READ_CPU_PKG, useful for uncore events, that
> allows a PMU to signal the generic perf code that an event is readable
> on the current CPU if the event is:
>   - active in a CPU in the same package as the current CPU (local CPU)

Ok that I get..

>   - not active but is attached to a CPU (i.e. event->cpu != -1) in the
>   same package as the current CPU.

but this, not so much. Why would you want to read an inactive counter?