Messages in this thread | | | Date | Mon, 22 Oct 2012 13:23:23 +0200 | Subject | Re: [PATCH 1/6] perf, x86: Basic Haswell LBR call stack support | From | Stephane Eranian <> |
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On Mon, Oct 22, 2012 at 12:33 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > > On Mon, 2012-10-22 at 14:11 +0800, Yan, Zheng wrote: > > + /* LBR callstack does not work well with FREEZE_LBRS_ON_PMI */ > > + if (!cpuc->lbr_sel || !(cpuc->lbr_sel->config & LBR_CALL_STACK)) > > + debugctl |= DEBUGCTLMSR_FREEZE_LBRS_ON_PMI; > Is this a bug or a feature?
> > How useful it is without this? How many calls between PMI and us getting > to intel_pmu_lbr_read()?
Agreed with Peter. Freeze on PMI is critical for LBR in general.
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