linux-kernel - Re: [PATCH V5 4/8] perf/x86/intel/uncore: add new data structures for free running counters

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Message-ID: <20180120012459.GL7844@tassilo.jf.intel.com>
Date:   Fri, 19 Jan 2018 17:24:59 -0800
From:   Andi Kleen <ak@...ux.intel.com>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     "Liang, Kan" <kan.liang@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "acme@...nel.org" <acme@...nel.org>
Subject: Re: [PATCH V5 4/8] perf/x86/intel/uncore: add new data structures
 for free running counters

On Fri, Jan 19, 2018 at 12:51:08PM -0800, Stephane Eranian wrote:
> On Fri, Jan 19, 2018 at 12:50 PM, Stephane Eranian <eranian@...gle.com> wrote:
> > On Fri, Jan 19, 2018 at 12:24 PM, Andi Kleen <ak@...ux.intel.com> wrote:
> >>> Oh, think a bit more.
> >>> I think we cannot do the same thing as we did for CPU PMU's fixed counters.
> >>>
> >>> The counters here are free running counters. They cannot be start/stop.
> >>
> >> Yes free running counter have completely different semantics. They
> >> need a separate event code.
> >>
> > Are you saying, you can be shared with no multiplexing?
> >
> Obviously not you, but the counters ;-)

Yes free running can be always shared.

-Andi