On Thu, May 07, 2015 at 03:56:31PM -0700, Andi Kleen wrote: > From: Andi Kleen <[email protected]> > > In Arch perfmon v4 the GLOBAL_STATUS reset automatically unfreezes > LBRs. So no need to do it manually in the LBR code. Add a check > to skip it. > > Signed-off-by: Andi Kleen <[email protected]> > --- > arch/x86/kernel/cpu/perf_event_intel_lbr.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c > b/arch/x86/kernel/cpu/perf_event_intel_lbr.c > index 6c48c97..64d3122 100644 > --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c > +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c > @@ -147,6 +147,13 @@ static void __intel_pmu_lbr_enable(bool pmi) > wrmsrl(MSR_LBR_SELECT, lbr_select); > } > > + /* > + * No need to unfreeze manually, as v4 can do that as part > + * of the GLOBAL_STATUS ack. > + */ > + if (pmi && x86_pmu.version >= 4) > + return; > +
But that block above is !pmi, so strictly exclusive with this condition. So why not put this at the start? > rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl); > orig_debugctl = debugctl; > debugctl |= DEBUGCTLMSR_LBR; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
