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Subject: Re: [PATCH 0/2] perf: Use LBR for machine/oops debugging
From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: mingo@elte.hu, Linus Torvalds <torvalds@osdl.org>,
       linux-kernel@vger.kernel.org, Stephane Eranian <eranian@google.com>
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References: <20100329122021.765109681@chello.nl>
	 <87bpe7qnrg.fsf@basil.nowhere.org>
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Date: Mon, 29 Mar 2010 16:14:19 +0200
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On Mon, 2010-03-29 at 15:08 +0200, Andi Kleen wrote:
> Peter Zijlstra <a.p.zijlstra@chello.nl> writes:
> 
> > The LBRs are relatively cheap to keep enabled and provide some history
> > to OOPSen, also some CPUs are reported to keep them over soft-reset,
> > which allows us to use them to debug things like tripple faults.
> >
> > Therefore introduce a boot option: lbr_debug=on, which always enable
> > the LBRs and will print the LBRs on CPU init and die().
> 
> 
> die is too late. they will only contain the oops code then.

We do an lbr_off() in oops_begin(), or is there a better/earlier place
we can do that?