linux-kernel - Re: [PATCH 4/7] perf, x86: Implement IBS interrupt handler

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Message-ID: <20110812180747.GH11702@erda.amd.com>
Date:	Fri, 12 Aug 2011 20:07:47 +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 4/7] perf, x86: Implement IBS interrupt handler

On 02.08.11 07:43:28, Peter Zijlstra wrote:
> On Thu, 2011-07-28 at 15:46 +0200, Robert Richter wrote:
> > +       msr = hwc->config_base;
> > +       buf = buffer;
> > +       rdmsrl(msr++, *buf);
> > +       if (!(*buf++ & perf_ibs->valid_mask))
> > +               return 0;
> > +
> > +       perf_sample_data_init(&data, 0);
> > +       if (event->attr.sample_type & PERF_SAMPLE_RAW) {
> > +               for (i = 1; i < perf_ibs->reg_count; i++)
> > +                       rdmsrl(msr++, *buf++);
> > +               raw.size = sizeof(u32) + sizeof(u64) * perf_ibs->reg_count;
> > +               raw.data = buffer;
> > +               data.raw = &raw;
> > +       } 
> 
> OK, so this dumps a linear range of MSRs into the raw data buffer. The
> only 'problem' I have with that is that Fam12 will then also dump 103A
> IBS Control Register, which seems pointless.

I will implement a bit mask instead. We can then use
for_each_set_bit() etc.

-Robert

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

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