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Subject: Re: [PATCH v2] Add PPC_FEATURE_PSERIES_PMU_COMPAT
Date: Tue, 8 Jul 2008 17:05:51 -0500
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Cc: Olof Johansson <olof@lixom.net>, linuxppc-dev@ozlabs.org,
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On Jul 8, 2008, at 3:01 PM, Nathan Lynch wrote:

> Background from Maynard Johnson:
> As of POWER6, a set of 32 common events is defined that must be
> supported on all future POWER processors.  The main impetus for this
> compat set is the need to support partition migration, especially from
> processor P(n) to processor P(n+1), where performance software that's
> running in the new partition may not be knowledgeable about processor
> P(n+1).  If a performance tool determines it does not support the
> physical processor, but is told (via the  
> PPC_FEATURE_PSERIES_PMU_COMPAT
> bit) that the processor supports the notion of the PMU compat set,
> then the performance tool can surface just those events to the user
> of the tool.
>
> PPC_FEATURE_PSERIES_PMU_COMPAT indicates that the PMU supports at
> least this basic subset of events which is compatible across POWER
> processor lines.
>
> Signed-off-by: Nathan Lynch <ntl@pobox.com>
> ---

So is PMU here performance monitor unit?  I think that was part of my  
confusion earlier.  I was thinking Power Mgmt Unit (like on Apple HW).

I hate make the name longer, but PPC_FEATURE_PSERIES_PERFMON_COMPAT  
would probably be clearer.

- k