linux-kernel - Re: [PATCH 7/7] perf, x86: Implement 64 bit counter support for IBS

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Date:	Fri, 12 Aug 2011 20:11:45 +0200
From:	Robert Richter <robert.richter@....com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	Ingo Molnar <mingo@...e.hu>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 7/7] perf, x86: Implement 64 bit counter support for IBS

On 02.08.11 07:37:20, Peter Zijlstra wrote:
> On Thu, 2011-07-28 at 15:46 +0200, Robert Richter wrote:
> > +       /*
> > +        * Emulate IbsOpCurCnt in MSRC001_1033 (IbsOpCtl), not
> > +        * supported in all cpus. As this triggered an interrupt, we
> > +        * set the current count to the max count.
> > +        */
> > +       config = buffer[0];
> > +       if (perf_ibs == &perf_ibs_op) {
> > +               config &= ~IBS_OP_CUR_CNT;
> > +               config |= (config & IBS_OP_MAX_CNT) << 36;
> > +       } 
> 
> Shouldn't that be conditional on capability muck?

It doesn't hurt actually, but true, will implement it right with the
capability check.

-Robert

-- 
Advanced Micro Devices, Inc.
Operating System Research Center

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