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    SubjectRe: [RFC,PATCH 2/2] perf, x86: Utilize the LBRs for machine/oops debugging
    On Mon, 2010-03-29 at 13:47 +0100, Stephane Eranian wrote:
    > On Mon, Mar 29, 2010 at 1:20 PM, Peter Zijlstra <> 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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