linux-kernel - Re: [PATCH 2/2] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs

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Message-ID: <ZjS0Uio+nvZLLmyb@gmail.com>
Date: Fri, 3 May 2024 11:54:26 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>
Cc: tglx@...utronix.de, bp@...en8.de, dave.hansen@...ux.intel.com,
	x86@...nel.org, peterz@...radead.org, mingo@...hat.com,
	ananth.narayan@....com, gautham.shenoy@....com,
	linux-perf-users@...r.kernel.org, linux-hardening@...r.kernel.org,
	linux-kernel@...r.kernel.org, sandipan.das@....com,
	alexander.shishkin@...ux.intel.com, irogers@...gle.com,
	gustavoars@...nel.org, kprateek.nayak@....com,
	ravi.bangoria@....com
Subject: Re: [PATCH 2/2] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs


* Dhananjay Ugwekar <Dhananjay.Ugwekar@....com> 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@....com>
> Fixes: 63edbaa48a57 ("x86/cpu/topology: Add support for the AMD 0x80000026 leaf")
> ---
>  arch/x86/events/rapl.c | 30 ++++++++++++++++++++++++++----
>  1 file changed, 26 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
> index 46e673585560..d77bf7959a43 100644
> --- a/arch/x86/events/rapl.c
> +++ b/arch/x86/events/rapl.c
> @@ -102,6 +102,10 @@ static struct perf_pmu_events_attr event_attr_##v = {				\
>  	.event_str	= str,							\
>  };
>  
> +#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;
> @@ -139,9 +143,21 @@ static unsigned int rapl_cntr_mask;
>  static u64 rapl_timer_ms;
>  static struct perf_msr *rapl_msrs;
>  
> +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 cpumask_t *get_rapl_pmu_cpumask(int cpu)
> +{
> +	return rapl_pmu_is_pkg_scope() ? topology_core_cpumask(cpu) :
> +					 topology_die_cpumask(cpu);
> +}

Note that this breaks the build with this config:

  https://download.01.org/0day-ci/archive/20240503/202405030828.RgFuznL9-lkp@intel.com/config

I've removed the commit from perf/core for now.

Thanks,

	Ingo