Re: [PATCH 2/4] perf, x86: Add Intel SandyBridge uncore pmu

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Thu, 2011-06-30 at 08:09 +0000, Lin Ming wrote:
> +static struct uncore_config {
> +       unsigned long config_base;
> +       unsigned long event_base;
> +} snb_uncore_configs[SNB_UNCORE_NUM_COUNTERS] = {
> +       {SNB_MSR_UNC_CBO_0_PERFEVTSEL0, SNB_MSR_UNC_CBO_0_PER_CTR0},
> +       {SNB_MSR_UNC_CBO_0_PERFEVTSEL1, SNB_MSR_UNC_CBO_0_PER_CTR1},
> +       {SNB_MSR_UNC_CBO_1_PERFEVTSEL0, SNB_MSR_UNC_CBO_1_PER_CTR0},
> +       {SNB_MSR_UNC_CBO_1_PERFEVTSEL1, SNB_MSR_UNC_CBO_1_PER_CTR1},
> +       {SNB_MSR_UNC_CBO_2_PERFEVTSEL0, SNB_MSR_UNC_CBO_2_PER_CTR0},
> +       {SNB_MSR_UNC_CBO_2_PERFEVTSEL1, SNB_MSR_UNC_CBO_2_PER_CTR1},
> +       {SNB_MSR_UNC_CBO_3_PERFEVTSEL0, SNB_MSR_UNC_CBO_3_PER_CTR0},
> +       {SNB_MSR_UNC_CBO_3_PERFEVTSEL1, SNB_MSR_UNC_CBO_3_PER_CTR1},
> +};

> +static int snb_uncore_pmu_hw_config(struct perf_event *event)
> +{
> +       struct hw_perf_event *hwc = &event->hw;
> +       int i = hwc->idx;
> +
> +       hwc->config = event->attr.config & SNB_UNCORE_RAW_EVENT_MASK;
> +       hwc->config_base = snb_uncore_configs[i].config_base;

	hwc->config_base = SNB_MSR_UNC_CBO_0_PERFEVTSEL0 + 
		0x10 * (i >> 1) + 0x6 * (i & 1);

Saves a memory lookup, might or might not be worth it.

What the heck did Intel mess those MSRs up for anyway?

> +       hwc->event_base = snb_uncore_configs[i].event_base;
> +
> +       return 0;
> +}