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

Stephane Eranian
2015-04-06T17:30:36Z

On Mon, Apr 6, 2015 at 8:21 AM, Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:
>
> 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?
>
I think the patch is fine.
Reviewed-by: Stephane Eranian <eranian@google.com>

>
> 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]