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

Dhananjay Ugwekar
2024-09-05T15:39:58Z

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.

So, change the PMU scope for AMD and Hygon back to package.

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>
---
v3 Link: https://lore.kernel.org/all/20240904100934.3260-1-Dhananjay.Ugwekar@amd.com/

Changes from v3:
* Move the rapl_pmu_is_pkg_scope() check before the memory allocation for rapl_pmus

tip/master + PMU scope patchset [1] to be taken as base for testing this patch.

[1]: https://lore.kernel.org/all/20240802151643.1691631-1-kan.liang@linux.intel.com/
---
arch/x86/events/rapl.c | 36 +++++++++++++++++++++++++++++++++---
1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index b70ad880c5bc..b13db61fc256 100644
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -139,9 +139,32 @@ static unsigned int rapl_cntr_mask;
static u64 rapl_timer_ms;
static struct perf_msr *rapl_msrs;

+/*
+ * RAPL Package energy counter scope:
+ * 1. AMD/HYGON platforms have a per-PKG package energy counter
+ * 2. For Intel platforms
+ * 2.1. CLX-AP is multi-die and its RAPL MSRs are die-scope
+ * 2.2. Other Intel platforms are single die systems so the scope can be
+ * considered as either pkg-scope or die-scope, and we are considering
+ * them as die-scope.
+ */
+#define rapl_pmu_is_pkg_scope() \
+ (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || \
+ boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
+
+/*
+ * Helper function to get the correct topology id 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 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
@@ -617,7 +640,7 @@ static void __init init_rapl_pmu(void)
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[get_rapl_pmu_idx(cpu)] = pmu;
}

cpus_read_unlock();
@@ -626,6 +649,12 @@ static void __init init_rapl_pmu(void)
static int __init init_rapl_pmus(void)
{
int nr_rapl_pmu = topology_max_packages() * topology_max_dies_per_package();
+ int rapl_pmu_scope = PERF_PMU_SCOPE_DIE;
+
+ if (rapl_pmu_is_pkg_scope()) {
+ nr_rapl_pmu = topology_max_packages();
+ rapl_pmu_scope = PERF_PMU_SCOPE_PKG;
+ }

rapl_pmus = kzalloc(struct_size(rapl_pmus, pmus, nr_rapl_pmu), GFP_KERNEL);
if (!rapl_pmus)
@@ -643,9 +672,10 @@ static int __init init_rapl_pmus(void)
rapl_pmus->pmu.start = rapl_pmu_event_start;
rapl_pmus->pmu.stop = rapl_pmu_event_stop;
rapl_pmus->pmu.read = rapl_pmu_event_read;
+ rapl_pmus->pmu.scope = rapl_pmu_scope;
rapl_pmus->pmu.module = THIS_MODULE;
- rapl_pmus->pmu.scope = PERF_PMU_SCOPE_DIE;
rapl_pmus->pmu.capabilities = PERF_PMU_CAP_NO_EXCLUDE;
+
return 0;
}

--
2.34.1