Re: [PATCH 0/2] perf: Use LBR for machine/oops debugging

From: Peter Zijlstra
Date: Mon Mar 29 2010 - 10:14:26 EST


On Mon, 2010-03-29 at 15:08 +0200, Andi Kleen wrote:
> Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> 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?

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