Messages in this thread | | | Date | Tue, 30 Jun 2020 18:42:25 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH V2 14/23] perf/x86/intel/lbr: Support Architectural LBR |
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On Tue, Jun 30, 2020 at 12:17:57PM -0400, Liang, Kan wrote:
> > > +static inline bool is_lbr_call_stack_bit_set(u64 config) > > > +{ > > > + if (x86_pmu.arch_lbr) > > > + return !!(config & ARCH_LBR_CALL_STACK); > > > + > > > + return !!(config & LBR_CALL_STACK); > > > +}
> > > + x86_pmu.arch_lbr = true;
> > How about we make this here clear FEATURE_ARCH_LBR if it fails and then > > do away with x86_pmu.arch_lbr and use > > static_cpu_has(X86_FEATURE_ARCH_LBR) a lot more? > > Yes, it's doable. So we can save a bit for arch_lbr in structure x86_pmu.
Mostly it's about getting rid of a load-test-branch.
> I will clear the FEATURE_ARCH_LBR via clear_cpu_cap(&boot_cpu_data, > X86_FEATURE_ARCH_LBR);, if the check fails. > I will replace x86_pmu.arch_lbr with static_cpu_has(X86_FEATURE_ARCH_LBR) > everywhere.
Thanks!
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