x86_pmu.enable() is called from x86_pmu_enable() with cpuc->enabled set to 0. This means we weren't re-enabling the counters after a context switch.
This patch just removes the check, as it should't be necessary (and the equivelent x86_ generic code does not have the checks). The origin of this problem is the KNC driver being based on the P6 one. The P6 driver also has this issue, but works anyway due to various lucky accidents. Signed-off-by: Vince Weaver <[email protected]> diff -ur linux-3.7-rc1.orig/arch/x86/kernel/cpu/perf_event_knc.c linux-3.7-rc1/arch/x86/kernel/cpu/perf_event_knc.c --- linux-3.7-rc1.orig/arch/x86/kernel/cpu/perf_event_knc.c 2012-10-14 17:41:04.000000000 -0400 +++ linux-3.7-rc1/arch/x86/kernel/cpu/perf_event_knc.c 2012-10-17 11:48:22.952394235 -0400 @@ -173,26 +173,22 @@ static inline void knc_pmu_disable_event(struct perf_event *event) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; u64 val; val = hwc->config; - if (cpuc->enabled) - val &= ~ARCH_PERFMON_EVENTSEL_ENABLE; + val &= ~ARCH_PERFMON_EVENTSEL_ENABLE; (void)wrmsrl_safe(hwc->config_base + hwc->idx, val); } static void knc_pmu_enable_event(struct perf_event *event) { - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); struct hw_perf_event *hwc = &event->hw; u64 val; val = hwc->config; - if (cpuc->enabled) - val |= ARCH_PERFMON_EVENTSEL_ENABLE; + val |= ARCH_PERFMON_EVENTSEL_ENABLE; (void)wrmsrl_safe(hwc->config_base + hwc->idx, val); } -- 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/
