Messages in this thread | | | Date | Fri, 07 Sep 2018 14:45:24 +0800 | From | Wei Wang <> | Subject | Re: [PATCH v2 1/8] perf/x86: add a function to get the lbr stack |
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On 09/07/2018 11:28 AM, Andi Kleen wrote: >> +int perf_get_lbr_stack(struct perf_lbr_stack *stack) >> +{ >> + stack->lbr_nr = x86_pmu.lbr_nr; >> + stack->lbr_tos = x86_pmu.lbr_tos; >> + stack->lbr_from = x86_pmu.lbr_from; >> + stack->lbr_to = x86_pmu.lbr_to; >> + >> + if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO) >> + stack->lbr_info = MSR_LBR_INFO_0; >> + else >> + stack->lbr_info = 0; > Seems weird to export the enum value if the enum isn't exported. > How can it be used? >
I'm not sure about the issue. The caller gets the value of MSR_LBR_INFO_0 (not the enum, LBR_FORMAT_INFO) only when the hardware supports it. If hardware doesn't support it, just sets it to 0, and there will be no lbr info msr to be passed through.
Best, Wei
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