Date: Fri, 29 Apr 2011 18:49:51 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Andi Kleen <ak@linux.intel.com>
Cc: Vince Weaver <vweaver1@eecs.utk.edu>, torvalds@linux-foundation.org,
        linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Stephane Eranian <eranian@gmail.com>
Subject: Re: re-enable Nehalem raw Offcore-Events support
Message-ID: <20110429164951.GB25491@elte.hu>
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* Andi Kleen <ak@linux.intel.com> wrote:

> On Fri, Apr 29, 2011 at 11:04:46AM -0400, Vince Weaver wrote:
> > Hello Linus
> > 
> > can you revert the commit b52c55c6a25e4515b5e075a989ff346fc251ed09
> 
> Acked-by: Andi Kleen <ak@linux.intel.com>

I outlined my objections in my reply to Vince.

> (I wrote the original patch)
> 
> > (finally!) added in the 2.6.39 merge window.  However this is a useful 
> > feature and many tools (including the PAPI performance counter library 
> > that I work on) had added support for it in anticipation of the 2.6.39 
> 
> I also use some tools which benefit from this functionality. The extended raw 
> events are very useful to analyze NUMA problems for once.

Mind sharing those methods and help generalizing them and help making them 
useful to non-experts? Peter's patch which adds a 'NUMA' level to the cache 
event abstractions could be a good start.

Only once generalization has been covered sufficiently, once we are sure we can 
stick with the raw ABI, can we push that upstream.

Thanks,

	Ingo
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