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

[Jacob Pan <jacob.jun.pan@linux.intel.com>]

On Mon, 6 Apr 2015 10:30:33 -0700
Stephane Eranian <eranian@google.com> wrote:

> 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>
> 
Hi Peter,

Any more comments? This is really a bug fix.

Thanks,


Jacob

> >
> > 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]

[Jacob Pan]