Re: [PATCH v4 02/11] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs

Dhananjay Ugwekar
2024-07-12T03:29:09Z

Hello Rui,

On 7/12/2024 7:34 AM, Zhang, Rui wrote:
> On Thu, 2024-07-11 at 10:24 +0000, Dhananjay Ugwekar wrote:
>> After commit ("x86/cpu/topology: Add support for the AMD 0x80000026
>> leaf"),
>> on AMD processors that support extended CPUID leaf 0x80000026, the
>> topology_die_cpumask() and topology_logical_die_id() macros, no
>> longer
>> return the package cpumask and package id, instead they return the
>> CCD
>> (Core Complex Die) mask and id respectively. This leads to the
>> energy-pkg
>> event scope to be modified to CCD instead of package.
>>
>> Replacing these macros with their package counterparts fixes the
>> energy-pkg event for AMD CPUs.
>>
>> However due to the difference between the scope of energy-pkg event
>> for
>> Intel and AMD CPUs, we have to replace these macros conditionally
>> only for
>> AMD CPUs.
>>
>> On a 12 CCD 1 Package AMD Zen4 Genoa machine:
>>
>> Before:
>> $ cat /sys/devices/power/cpumask
>> 0,8,16,24,32,40,48,56,64,72,80,88.
>>
>> The expected cpumask here is supposed to be just "0", as it is a
>> package
>> scope event, only one CPU will be collecting the event for all the
>> CPUs in
>> the package.
>>
>> After:
>> $ cat /sys/devices/power/cpumask
>> 0
>>
>> Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@amd.com>
>> Fixes: 63edbaa48a57 ("x86/cpu/topology: Add support for the AMD
>> 0x80000026 leaf")
>
> You still missed my Reviewed-by tag for this one. :)
> https://lore.kernel.org/all/e1f70a09f85dbd0ee3f32dffea37993e141269d0.camel@intel.com/

I didnt forget this time, just wanted to give you a chance to review the changes :) (although they are minimal)

Will surely add it in next version!

Thanks,
Dhananjay

>
> thanks,
> rui
>
>> ---
>> Changes in v4:
>> * Invert the pkg scope check in init_rapl_pmus() (Peter)
>> * Add comments to explain the pkg scope check (Peter)
>>
>> PS: Scope check logic is still kept the same (i.e., all Intel systems
>> being
>> considered as die scope), Rui will be modifying it to limit the die-
>> scope
>> only to Cascadelake-AP in a future patch on top of this patchset.
>> ---
>>  arch/x86/events/rapl.c | 39 ++++++++++++++++++++++++++++++++++-----
>>  1 file changed, 34 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
>> index 0c5e7a7c43ac..df71f38ad98d 100644
>> --- a/arch/x86/events/rapl.c
>> +++ b/arch/x86/events/rapl.c
>> @@ -103,6 +103,13 @@ static struct perf_pmu_events_attr
>> event_attr_##v = {                              \
>>         .event_str      =
>> str,                                                  \
>>  };
>>
>> +/*
>> + * RAPL PMU scope for AMD is package whereas for Intel it is die.
>> + */
>> +#define rapl_pmu_is_pkg_scope()                                \
>> +       (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||  \
>> +        boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
>> +
>>  struct rapl_pmu {
>>         raw_spinlock_t          lock;
>>         int                     n_active;
>> @@ -140,9 +147,25 @@ static unsigned int rapl_cntr_mask;
>>  static u64 rapl_timer_ms;
>>  static struct perf_msr *rapl_msrs;
>>
>> +/*
>> + * Helper functions to get the correct topology macros according to
>> the
>> + * RAPL PMU scope.
>> + */
>> +static inline unsigned int get_rapl_pmu_idx(int cpu)
>> +{
>> +       return rapl_pmu_is_pkg_scope() ?
>> topology_logical_package_id(cpu) :
>> +
>> topology_logical_die_id(cpu);
>> +}
>> +
>> +static inline const struct cpumask *get_rapl_pmu_cpumask(int cpu)
>> +{
>> +       return rapl_pmu_is_pkg_scope() ? topology_core_cpumask(cpu) :
>> +                                        topology_die_cpumask(cpu);
>> +}
>> +
>>  static inline struct rapl_pmu *cpu_to_rapl_pmu(unsigned int cpu)
>>  {
>> -       unsigned int rapl_pmu_idx = topology_logical_die_id(cpu);
>> +       unsigned int rapl_pmu_idx = get_rapl_pmu_idx(cpu);
>>
>>         /*
>>          * The unsigned check also catches the '-1' return value for
>> non
>> @@ -543,6 +566,7 @@ static struct perf_msr amd_rapl_msrs[] = {
>>
>>  static int rapl_cpu_offline(unsigned int cpu)
>>  {
>> +       const struct cpumask *rapl_pmu_cpumask =
>> get_rapl_pmu_cpumask(cpu);
>>         struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
>>         int target;
>>
>> @@ -552,7 +576,7 @@ static int rapl_cpu_offline(unsigned int cpu)
>>
>>         pmu->cpu = -1;
>>         /* Find a new cpu to collect rapl events */
>> -       target = cpumask_any_but(topology_die_cpumask(cpu), cpu);
>> +       target = cpumask_any_but(rapl_pmu_cpumask, cpu);
>>
>>         /* Migrate rapl events to the new target */
>>         if (target < nr_cpu_ids) {
>> @@ -565,6 +589,8 @@ static int rapl_cpu_offline(unsigned int cpu)
>>
>>  static int rapl_cpu_online(unsigned int cpu)
>>  {
>> +       unsigned int rapl_pmu_idx = get_rapl_pmu_idx(cpu);
>> +       const struct cpumask *rapl_pmu_cpumask =
>> get_rapl_pmu_cpumask(cpu);
>>         struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
>>         int target;
>>
>> @@ -579,14 +605,14 @@ static int rapl_cpu_online(unsigned int cpu)
>>                 pmu->timer_interval = ms_to_ktime(rapl_timer_ms);
>>                 rapl_hrtimer_init(pmu);
>>
>> -               rapl_pmus->pmus[topology_logical_die_id(cpu)] = pmu;
>> +               rapl_pmus->pmus[rapl_pmu_idx] = pmu;
>>         }
>>
>>         /*
>>          * Check if there is an online cpu in the package which
>> collects rapl
>>          * events already.
>>          */
>> -       target = cpumask_any_and(&rapl_cpu_mask,
>> topology_die_cpumask(cpu));
>> +       target = cpumask_any_and(&rapl_cpu_mask, rapl_pmu_cpumask);
>>         if (target < nr_cpu_ids)
>>                 return 0;
>>
>> @@ -675,7 +701,10 @@ static const struct attribute_group
>> *rapl_attr_update[] = {
>>
>>  static int __init init_rapl_pmus(void)
>>  {
>> -       int nr_rapl_pmu = topology_max_packages() *
>> topology_max_dies_per_package();
>> +       int nr_rapl_pmu = topology_max_packages();
>> +
>> +       if (!rapl_pmu_is_pkg_scope())
>> +               nr_rapl_pmu *= topology_max_dies_per_package();
>>
>>         rapl_pmus = kzalloc(struct_size(rapl_pmus, pmus,
>> nr_rapl_pmu), GFP_KERNEL);
>>         if (!rapl_pmus)
>