Messages in this thread | | | Subject | Re: [RFC,PATCH 2/2] perf, x86: Utilize the LBRs for machine/oops debugging | From | Peter Zijlstra <> | Date | Mon, 29 Mar 2010 16:13:44 +0200 |
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On Mon, 2010-03-29 at 13:47 +0100, Stephane Eranian wrote: > On Mon, Mar 29, 2010 at 1:20 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > > 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(). > > > > When this is enabled, it will prevent changing the LBR configuration to > record only selected branches. Unless you are willing to accept filtered > content in the kernel dump.
Sure, but since we don't support that silly config reg anyway that's pretty much not an issue ;-)
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