[PATCH v4 02/11] perf/x86/rapl: Fix the energy-pkg event for AMD CPUs

Dhananjay Ugwekar
2024-07-11T10:28:10Z

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@amd.com>
Fixes: 63edbaa48a57 ("x86/cpu/topology: Add support for the AMD 0x80000026 leaf")
---
Changes in v4:
* Invert the pkg scope check in init_rapl_pmus() (Peter)
* Add comments to explain the pkg scope check (Peter)

PS: Scope check logic is still kept the same (i.e., all Intel systems being
considered as die scope), Rui will be modifying it to limit the die-scope
only to Cascadelake-AP in a future patch on top of this patchset.
---
arch/x86/events/rapl.c | 39 ++++++++++++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index 0c5e7a7c43ac..df71f38ad98d 100644
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -103,6 +103,13 @@ static struct perf_pmu_events_attr event_attr_##v = { \
.event_str = str, \
};

+/*
+ * RAPL PMU scope for AMD is package whereas for Intel it is die.
+ */
+#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;
@@ -140,9 +147,25 @@ static unsigned int rapl_cntr_mask;
static u64 rapl_timer_ms;
static struct perf_msr *rapl_msrs;

+/*
+ * Helper functions to get the correct topology macros 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 const struct cpumask *get_rapl_pmu_cpumask(int cpu)
+{
+ return rapl_pmu_is_pkg_scope() ? topology_core_cpumask(cpu) :
+ topology_die_cpumask(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
@@ -543,6 +566,7 @@ static struct perf_msr amd_rapl_msrs[] = {

static int rapl_cpu_offline(unsigned int cpu)
{
+ const struct cpumask *rapl_pmu_cpumask = get_rapl_pmu_cpumask(cpu);
struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
int target;

@@ -552,7 +576,7 @@ static int rapl_cpu_offline(unsigned int cpu)

pmu->cpu = -1;
/* Find a new cpu to collect rapl events */
- target = cpumask_any_but(topology_die_cpumask(cpu), cpu);
+ target = cpumask_any_but(rapl_pmu_cpumask, cpu);

/* Migrate rapl events to the new target */
if (target < nr_cpu_ids) {
@@ -565,6 +589,8 @@ static int rapl_cpu_offline(unsigned int cpu)

static int rapl_cpu_online(unsigned int cpu)
{
+ unsigned int rapl_pmu_idx = get_rapl_pmu_idx(cpu);
+ const struct cpumask *rapl_pmu_cpumask = get_rapl_pmu_cpumask(cpu);
struct rapl_pmu *pmu = cpu_to_rapl_pmu(cpu);
int target;

@@ -579,14 +605,14 @@ static int rapl_cpu_online(unsigned int cpu)
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[rapl_pmu_idx] = pmu;
}

/*
* Check if there is an online cpu in the package which collects rapl
* events already.
*/
- target = cpumask_any_and(&rapl_cpu_mask, topology_die_cpumask(cpu));
+ target = cpumask_any_and(&rapl_cpu_mask, rapl_pmu_cpumask);
if (target < nr_cpu_ids)
return 0;

@@ -675,7 +701,10 @@ static const struct attribute_group *rapl_attr_update[] = {

static int __init init_rapl_pmus(void)
{
- int nr_rapl_pmu = topology_max_packages() * topology_max_dies_per_package();
+ int nr_rapl_pmu = topology_max_packages();
+
+ if (!rapl_pmu_is_pkg_scope())
+ nr_rapl_pmu *= topology_max_dies_per_package();

rapl_pmus = kzalloc(struct_size(rapl_pmus, pmus, nr_rapl_pmu), GFP_KERNEL);
if (!rapl_pmus)
--
2.34.1