Re: [PATCH 06/12] perf/x86-ibs: Precise event sampling with IBS forAMD CPUs

From: Peter Zijlstra
Date: Mon Apr 23 2012 - 06:37:03 EST


On Mon, 2012-04-23 at 10:41 +0200, Robert Richter wrote:
> On 14.04.12 12:22:10, Peter Zijlstra wrote:
> > On Mon, 2012-04-02 at 20:19 +0200, Robert Richter wrote:
> > > + * IbsOpCntCtl (bit 19) of IBS Execution Control Register (IbsOpCtl,
> > > + * MSRC001_1033) is used to select either cycle or micro-ops counting
> > > + * mode.
> >
> > Ah is that what it does.. the BKDG doesn't appear to say this.
>
> "19 IbsOpCntCtl: periodic op counter count control. Revision B:
> Reserved. Revision C: Read-write. Reset 0b. 1=Count dispatched ops
> 0=Count clock cycles."
>
> It's here:
>
> MSRC001_1033 IBS Execution Control Register (IbsOpCtl)
> http://support.amd.com/us/Processor_TechDocs/31116.pdf
>
> Ok, it might not be quite clear that "dispatched ops" is related to
> EventSelect 0C1h Retired uops, but there is an exact mapping.

Ah, looks like my docs are stale.. my fam10 doc didn't have it specified
at all and my fam12 doc just listed the bit 19 as "periodic op counter
count control. Read-write." Which isn't very helpful.

Thanks!
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