Re: [PATCH v3] perf/rapl: support per domain energy unit

Jacob Pan
2015-04-06T15:22:43Z

On Thu, 26 Mar 2015 14:28:45 -0700
Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:

> RAPL energy hardware unit can vary within a single CPU package, e.g.
> HSW server DRAM has a fixed energy unit of 15.3 uJ (2^-16) whereas
> the unit on other domains can be enumerated from power unit MSR.
> There might be other variations in the future, this patch adds
> per cpu model quirk to allow special handling of certain cpus.
>
> hw_unit is also removed from per cpu data since it is not per cpu
> and the sampling rate for energy counter is typically not high.
>
> Without this patch, DRAM domain on HSW servers will be counted
> 4x higher than the real energy counter.
>

are there any more comments about this patch?

Thanks,

Jacob
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> ---
> arch/x86/kernel/cpu/perf_event_intel_rapl.c | 94
> ++++++++++++++++++++++------- 1 file changed, 73 insertions(+), 21
> deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
> b/arch/x86/kernel/cpu/perf_event_intel_rapl.c index c4bb8b8..999289b9
> 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c
> @@ -62,6 +62,14 @@
> #define RAPL_IDX_PP1_NRG_STAT 3 /* gpu */
> #define INTEL_RAPL_PP1 0x4 /* pseudo-encoding
> */
> +#define NR_RAPL_DOMAINS 0x4
> +static const char *rapl_domain_names[NR_RAPL_DOMAINS] __initconst = {
> + "pp0-core",
> + "package",
> + "dram",
> + "pp1-gpu",
> +};
> +
> /* Clients have PP0, PKG */
> #define RAPL_IDX_CLN (1<<RAPL_IDX_PP0_NRG_STAT|\
> 1<<RAPL_IDX_PKG_NRG_STAT|\
> @@ -112,7 +120,6 @@ static struct perf_pmu_events_attr event_attr_##v
> = { \
> struct rapl_pmu {
> spinlock_t lock;
> - int hw_unit; /* 1/2^hw_unit Joule */
> int n_active; /* number of active events */
> struct list_head active_list;
> struct pmu *pmu; /* pointer to rapl_pmu_class */
> @@ -120,6 +127,7 @@ struct rapl_pmu {
> struct hrtimer hrtimer;
> };
>
> +static int rapl_hw_unit[NR_RAPL_DOMAINS] __read_mostly; /*
> 1/2^hw_unit Joule */ static struct pmu rapl_pmu_class;
> static cpumask_t rapl_cpu_mask;
> static int rapl_cntr_mask;
> @@ -127,6 +135,7 @@ static int rapl_cntr_mask;
> static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu);
> static DEFINE_PER_CPU(struct rapl_pmu *, rapl_pmu_to_free);
>
> +static struct x86_pmu_quirk *rapl_quirks;
> static inline u64 rapl_read_counter(struct perf_event *event)
> {
> u64 raw;
> @@ -134,15 +143,28 @@ static inline u64 rapl_read_counter(struct
> perf_event *event) return raw;
> }
>
> -static inline u64 rapl_scale(u64 v)
> +#define
> rapl_add_quirk(func_)
> \ +do
> {
> \
> + static struct x86_pmu_quirk __quirk __initdata =
> { \
> + .func =
> func_, \
> + };
> \
> + __quirk.next =
> rapl_quirks; \
> + rapl_quirks =
> &__quirk; \ +} while
> (0) +
> +static inline u64 rapl_scale(u64 v, int cfg)
> {
> + if (cfg > NR_RAPL_DOMAINS) {
> + pr_warn("invalid domain %d, failed to scale data\n",
> cfg);
> + return v;
> + }
> /*
> * scale delta to smallest unit (1/2^32)
> * users must then scale back: count * 1/(1e9*2^32) to get
> Joules
> * or use ldexp(count, -32).
> * Watts = Joules/Time delta
> */
> - return v << (32 - __this_cpu_read(rapl_pmu)->hw_unit);
> + return v << (32 - rapl_hw_unit[cfg - 1]);
> }
>
> static u64 rapl_event_update(struct perf_event *event)
> @@ -173,7 +195,7 @@ again:
> delta = (new_raw_count << shift) - (prev_raw_count << shift);
> delta >>= shift;
>
> - sdelta = rapl_scale(delta);
> + sdelta = rapl_scale(delta, event->hw.config);
>
> local64_add(sdelta, &event->count);
>
> @@ -546,12 +568,22 @@ static void rapl_cpu_init(int cpu)
> cpumask_set_cpu(cpu, &rapl_cpu_mask);
> }
>
> +static __init void rapl_hsw_server_quirk(void)
> +{
> + /*
> + * DRAM domain on HSW server has fixed energy unit which can
> be
> + * different than the unit from power unit MSR.
> + * "Intel Xeon Processor E5-1600 and E5-2600 v3 Product
> Families, V2
> + * of 2. Datasheet, September 2014, Reference Number:
> 330784-001 "
> + */
> + rapl_hw_unit[RAPL_IDX_RAM_NRG_STAT] = 16;
> +}
> +
> static int rapl_cpu_prepare(int cpu)
> {
> struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu);
> int phys_id = topology_physical_package_id(cpu);
> u64 ms;
> - u64 msr_rapl_power_unit_bits;
>
> if (pmu)
> return 0;
> @@ -559,24 +591,13 @@ static int rapl_cpu_prepare(int cpu)
> if (phys_id < 0)
> return -1;
>
> - /* protect rdmsrl() to handle virtualization */
> - if (rdmsrl_safe(MSR_RAPL_POWER_UNIT,
> &msr_rapl_power_unit_bits))
> - return -1;
> -
> pmu = kzalloc_node(sizeof(*pmu), GFP_KERNEL,
> cpu_to_node(cpu)); if (!pmu)
> return -1;
> -
> spin_lock_init(&pmu->lock);
>
> INIT_LIST_HEAD(&pmu->active_list);
>
> - /*
> - * grab power unit as: 1/2^unit Joules
> - *
> - * we cache in local PMU instance
> - */
> - pmu->hw_unit = (msr_rapl_power_unit_bits >> 8) & 0x1FULL;
> pmu->pmu = &rapl_pmu_class;
>
> /*
> @@ -586,8 +607,8 @@ static int rapl_cpu_prepare(int cpu)
> * divide interval by 2 to avoid lockstep (2 * 100)
> * if hw unit is 32, then we use 2 ms 1/200/2
> */
> - if (pmu->hw_unit < 32)
> - ms = (1000 / (2 * 100)) * (1ULL << (32 -
> pmu->hw_unit - 1));
> + if (rapl_hw_unit[0] < 32)
> + ms = (1000 / (2 * 100)) * (1ULL << (32 -
> rapl_hw_unit[0] - 1)); else
> ms = 2;
>
> @@ -655,6 +676,20 @@ static int rapl_cpu_notifier(struct
> notifier_block *self, return NOTIFY_OK;
> }
>
> +static int rapl_check_hw_unit(void)
> +{
> + u64 msr_rapl_power_unit_bits;
> + int i;
> +
> + /* protect rdmsrl() to handle virtualization */
> + if (rdmsrl_safe(MSR_RAPL_POWER_UNIT,
> &msr_rapl_power_unit_bits))
> + return -1;
> + for (i = 0; i < NR_RAPL_DOMAINS; i++)
> + rapl_hw_unit[i] = (msr_rapl_power_unit_bits >> 8) &
> 0x1FULL; +
> + return 0;
> +}
> +
> static const struct x86_cpu_id rapl_cpu_match[] = {
> [0] = { .vendor = X86_VENDOR_INTEL, .family = 6 },
> [1] = {},
> @@ -664,6 +699,8 @@ static int __init rapl_pmu_init(void)
> {
> struct rapl_pmu *pmu;
> int cpu, ret;
> + struct x86_pmu_quirk *quirk;
> + int i;
>
> /*
> * check for Intel processor family 6
> @@ -678,6 +715,11 @@ static int __init rapl_pmu_init(void)
> rapl_cntr_mask = RAPL_IDX_CLN;
> rapl_pmu_events_group.attrs = rapl_events_cln_attr;
> break;
> + case 63: /* Haswell-Server */
> + rapl_add_quirk(rapl_hsw_server_quirk);
> + rapl_cntr_mask = RAPL_IDX_SRV;
> + rapl_pmu_events_group.attrs = rapl_events_srv_attr;
> + break;
> case 60: /* Haswell */
> case 69: /* Haswell-Celeron */
> rapl_cntr_mask = RAPL_IDX_HSW;
> @@ -693,7 +735,13 @@ static int __init rapl_pmu_init(void)
> /* unsupported */
> return 0;
> }
> + ret = rapl_check_hw_unit();
> + if (ret)
> + return ret;
>
> + /* run cpu model quirks */
> + for (quirk = rapl_quirks; quirk; quirk = quirk->next)
> + quirk->func();
> cpu_notifier_register_begin();
>
> for_each_online_cpu(cpu) {
> @@ -714,14 +762,18 @@ static int __init rapl_pmu_init(void)
>
> pmu = __this_cpu_read(rapl_pmu);
>
> - pr_info("RAPL PMU detected, hw unit 2^-%d Joules,"
> + pr_info("RAPL PMU detected,"
> " API unit is 2^-32 Joules,"
> " %d fixed counters"
> " %llu ms ovfl timer\n",
> - pmu->hw_unit,
> hweight32(rapl_cntr_mask),
> ktime_to_ms(pmu->timer_interval));
> -
> + for (i = 0; i < NR_RAPL_DOMAINS; i++) {
> + if (rapl_cntr_mask & (1 << i)) {
> + pr_info("hw unit of domain %s 2^-%d
> Joules\n",
> + rapl_domain_names[i],
> rapl_hw_unit[i]);
> + }
> + }
> out:
> cpu_notifier_register_done();
>

[Jacob Pan]