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

["Zhang, Rui" <rui.zhang@intel.com>]

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@michaellarabel.com>
> > > Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@amd.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?

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