Re: [PATCH 2/2] powercap/intel_rapl: Fix the energy-pkg event for AMD CPUs

[Dhananjay Ugwekar]

Hi Rui,

On 7/21/2024 7:47 PM, Zhang, Rui wrote:
> On Fri, 2024-07-19 at 09:25 +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_logical_die_id() macros, no longer returns package id,
>> instead it
>> returns the CCD (Core Complex Die) id. This leads to the energy-pkg
>> event scope to be modified to CCD instead of package.
>>
>> For more historical context, please refer to commit 32fb480e0a2c
>> ("powercap/intel_rapl: Support multi-die/package"), which initially
>> changed
>> the RAPL scope from package to die for all systems, as Intel systems
>> with Die enumeration have RAPL scope as die, and those without die
>> enumeration are not affected. So, all systems(Intel, AMD, Hygon),
>> worked
>> correctly with topology_logical_die_id() until recently, but this
>> changed
>> after the "0x80000026 leaf" commit mentioned above.
>>
>> Replacing topology_logical_die_id() with
>> topology_physical_package_id()
>> conditionally only for AMD and Hygon fixes the energy-pkg event.
>>
>> On an AMD 2 socket 8 CCD Zen5 server:
>>
>> Before:
>>
>> linux$ ls /sys/class/powercap/
>> intel-rapl      intel-rapl:1:0  intel-rapl:3:0  intel-rapl:5:0
>> intel-rapl:7:0  intel-rapl:9:0  intel-rapl:b:0  intel-rapl:d:0
>> intel-rapl:f:0  intel-rapl:0    intel-rapl:2    intel-rapl:4
>> intel-rapl:6    intel-rapl:8    intel-rapl:a    intel-rapl:c
>> intel-rapl:e    intel-rapl:0:0  intel-rapl:2:0  intel-rapl:4:0
>> intel-rapl:6:0  intel-rapl:8:0  intel-rapl:a:0  intel-rapl:c:0
>> intel-rapl:e:0  intel-rapl:1    intel-rapl:3    intel-rapl:5
>> intel-rapl:7    intel-rapl:9    intel-rapl:b    intel-rapl:d
>> intel-rapl:f
>>
>> After:
>>
>> linux$ ls /sys/class/powercap/
>> intel-rapl  intel-rapl:0  intel-rapl:0:0  intel-rapl:1  intel-
>> rapl:1:0
>>
>> Only one sysfs entry per-event per-package is created after this
>> change.
>>
>> Fixes: 63edbaa48a57 ("x86/cpu/topology: Add support for the AMD
>> 0x80000026 leaf")
>> Reported-by: Michael Larabel <michael@xxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@xxxxxxx>
> 
> For the future Intel multi-die system that I know, it still has
> package-scope RAPL, but this is done with TPMI RAPL interface.
> 
> The TPMI RAPL driver invokes these APIs with "id == pkg_id" and
> "id_is_cpu == false", so no need to make rapl_pmu_is_pkg_scope()
> returns true for those Intel systems.

This seems like an important point, would you be okay with it, if I include
this info in the commit log in v2 along with you rb tag?

Thanks for the review.

Regards,
Dhananjay

> 
> The patch LGTM.
> 
> Reviewed-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> 
> thanks,
> rui
>> ---
>>  drivers/powercap/intel_rapl_common.c | 20 +++++++++++++++++---
>>  1 file changed, 17 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/powercap/intel_rapl_common.c
>> b/drivers/powercap/intel_rapl_common.c
>> index 3cffa6c79538..2f24ca764408 100644
>> --- a/drivers/powercap/intel_rapl_common.c
>> +++ b/drivers/powercap/intel_rapl_common.c
>> @@ -2128,6 +2128,18 @@ void rapl_remove_package(struct rapl_package
>> *rp)
>>  }
>>  EXPORT_SYMBOL_GPL(rapl_remove_package);
>>  
>> +/*
>> + * Intel systems that enumerate DIE domain have RAPL domains
>> implemented
>> + * per-die, however, the same is not true for AMD and Hygon
>> processors
>> + * where RAPL domains for PKG energy are in-fact per-PKG. Since
>> + * logical_die_id is same as logical_package_id in absence of DIE
>> + * enumeration, use topology_logical_die_id() on Intel systems and
>> + * topology_logical_package_id() on AMD and Hygon systems.
>> + */
>> +#define rapl_pmu_is_pkg_scope()                                \
>> +       (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||  \
>> +        boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
>> +
>>  /* caller to ensure CPU hotplug lock is held */
>>  struct rapl_package *rapl_find_package_domain_cpuslocked(int id,
>> struct rapl_if_priv *priv,
>>                                                          bool
>> id_is_cpu)
>> @@ -2136,7 +2148,8 @@ struct rapl_package
>> *rapl_find_package_domain_cpuslocked(int id, struct rapl_if_
>>         int uid;
>>  
>>         if (id_is_cpu)
>> -               uid = topology_logical_die_id(id);
>> +               uid = rapl_pmu_is_pkg_scope() ?
>> +                     topology_physical_package_id(id) :
>> topology_logical_die_id(id);
>>         else
>>                 uid = id;
>>  
>> @@ -2168,9 +2181,10 @@ struct rapl_package
>> *rapl_add_package_cpuslocked(int id, struct rapl_if_priv *pr
>>                 return ERR_PTR(-ENOMEM);
>>  
>>         if (id_is_cpu) {
>> -               rp->id = topology_logical_die_id(id);
>> +               rp->id = rapl_pmu_is_pkg_scope() ?
>> +                        topology_physical_package_id(id) :
>> topology_logical_die_id(id);
>>                 rp->lead_cpu = id;
>> -               if (topology_max_dies_per_package() > 1)
>> +               if (!rapl_pmu_is_pkg_scope() &&
>> topology_max_dies_per_package() > 1)
>>                         snprintf(rp->name,
>> PACKAGE_DOMAIN_NAME_LENGTH, "package-%d-die-%d",
>>                                  topology_physical_package_id(id),
>> topology_die_id(id));
>>                 else
>