Message-ID: <121f1f5e-9ba4-4793-b743-e36201bd881f@amd.com>
Date: Tue, 23 Jul 2024 09:42:52 +0530
From: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
To: "Zhang, Rui" <rui.zhang@...el.com>, "acme@...nel.org" <acme@...nel.org>,
 "alexander.shishkin@...ux.intel.com" <alexander.shishkin@...ux.intel.com>,
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Subject: Re: [PATCH 2/2] powercap/intel_rapl: Fix the energy-pkg event for AMD
 CPUs



On 7/22/2024 8:51 PM, Zhang, Rui wrote:
> On Mon, 2024-07-22 at 19:31 +0530, Dhananjay Ugwekar wrote:
>>
>>
>> On 7/22/2024 7:22 PM, Zhang, Rui wrote:
>>> On Mon, 2024-07-22 at 13:54 +0530, Dhananjay Ugwekar wrote:
>>>> 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@...haellarabel.com>
>>>>>> Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
>>>>>
>>>>> 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?
>>>
>>> Yes.
>>>
>>> This reminds me that we can rephrase the comment for
>>> rapl_pmu_is_pkg_scope() a bit, something including below points,
>>> 1. AMD/HYGON platforms use per-PKG Package energy counter
>>> 2. For Intel platforms
>>>    2.1 CLX-AP platform has per-DIE Package energy counter
>>>    2.2 other platforms that uses MSR RAPL are single die systems so
>>> the
>>> Package energy counter are per-PKG/per-DIE
>>>    2.3 new platforms that use TPMI RAPL doesn't care about the
>>> scope
>>> because they are not MSR/CPU based.
>>>
>>> what do you think?
>>
>> Agreed, this gives a more clear picture of the all the RAPL scopes.
>>
>> We will need the above comment in the first patch as well, apart from
>> the 2.3 point.
> 
> Sounds good to me.
>>
>> Also, regarding perf/x86/rapl driver(patch 1), will you be sending a
>> patch
>> to conditionally set the rapl scope to die for CLK-AP platform(on top
>> of this fix),
>> or should I fix it in this patch 1 itself?
> 
> patch 1 is a fix patch.
> optimization for CLX-AP should be a separate patch and that is not
> urgent (the new logic is still correct for current existing Intel
> platforms), I will submit it later.

Makes sense

> 
> I think the fix patch is good enough as long as we have below
> information
> 1. CLX-AP is multi-die and its RAPL MSRs are die scope
> 2. other Intel platforms are single die systems so the scope can be
> considered as either pkg-scope or die-scope.
> This info will make the future optimization easier.

Yes, this seems good

Thanks, 
Dhananjay

> 
> thanks,
> rui
> 
>>
>> Thanks,
>> Dhananjay
>>
>>>
>>> thanks,
>>> rui
>>>>
>>>> Thanks for the review.
>>>>
>>>> Regards,
>>>> Dhananjay
>>>>
>>>>>
>>>>> The patch LGTM.
>>>>>
>>>>> Reviewed-by: Zhang Rui <rui.zhang@...el.com>
>>>>>
>>>>> 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
>>>>>
>>>
>>
> 

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