[PATCH 1/8] perf/x86/uncore: Save the unit control address of all units

kan.liang
2024-06-10T20:17:52Z

The unit control address of some CXL units may be wrongly calculated
under some configuration on a EMR machine.

The current implementation only saves the unit control address of the
units from the first die, and the first unit of the rest of dies. Perf
assumed that the units from the other dies have the same offset as the
first die. So the unit control address of the rest of the units can be
calculated. However, the assumption is wrong, especially for the CXL
units.

Introduce an RB tree for each uncore type to save the unit control
address and ID information for all the units.

Compared with the current implementation, more space is required to save
the information of all units. The extra size should be acceptable.
For example, on EMR, there are 221 units at most. For a 2-socket machine,
the extra space is ~6KB at most.

Tested-by: Yunying Sun <yunying.sun@intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
arch/x86/events/intel/uncore_discovery.c | 79 +++++++++++++++++++++++-
arch/x86/events/intel/uncore_discovery.h | 10 +++
2 files changed, 87 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
index 9a698a92962a..ce520e69a3c1 100644
--- a/arch/x86/events/intel/uncore_discovery.c
+++ b/arch/x86/events/intel/uncore_discovery.c
@@ -93,6 +93,8 @@ add_uncore_discovery_type(struct uncore_unit_discovery *unit)
if (!type->box_ctrl_die)
goto free_type;

+ type->units = RB_ROOT;
+
type->access_type = unit->access_type;
num_discovered_types[type->access_type]++;
type->type = unit->box_type;
@@ -120,10 +122,59 @@ get_uncore_discovery_type(struct uncore_unit_discovery *unit)
return add_uncore_discovery_type(unit);
}

+static inline bool unit_less(struct rb_node *a, const struct rb_node *b)
+{
+ struct intel_uncore_discovery_unit *a_node, *b_node;
+
+ a_node = rb_entry(a, struct intel_uncore_discovery_unit, node);
+ b_node = rb_entry(b, struct intel_uncore_discovery_unit, node);
+
+ if (a_node->pmu_idx < b_node->pmu_idx)
+ return true;
+ if (a_node->pmu_idx > b_node->pmu_idx)
+ return false;
+
+ if (a_node->die < b_node->die)
+ return true;
+ if (a_node->die > b_node->die)
+ return false;
+
+ return 0;
+}
+
+static inline struct intel_uncore_discovery_unit *
+uncore_find_unit(struct rb_root *root, unsigned int id)
+{
+ struct intel_uncore_discovery_unit *unit;
+ struct rb_node *node;
+
+ for (node = rb_first(root); node; node = rb_next(node)) {
+ unit = rb_entry(node, struct intel_uncore_discovery_unit, node);
+ if (unit->id == id)
+ return unit;
+ }
+
+ return NULL;
+}
+
+static void uncore_find_add_unit(struct intel_uncore_discovery_unit *node,
+ struct rb_root *root, u16 *num_units)
+{
+ struct intel_uncore_discovery_unit *unit = uncore_find_unit(root, node->id);
+
+ if (unit)
+ node->pmu_idx = unit->pmu_idx;
+ else if (num_units)
+ node->pmu_idx = (*num_units)++;
+
+ rb_add(&node->node, root, unit_less);
+}
+
static void
uncore_insert_box_info(struct uncore_unit_discovery *unit,
int die, bool parsed)
{
+ struct intel_uncore_discovery_unit *node;
struct intel_uncore_discovery_type *type;
unsigned int *ids;
u64 *box_offset;
@@ -136,14 +187,26 @@ uncore_insert_box_info(struct uncore_unit_discovery *unit,
return;
}

+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return;
+
+ node->die = die;
+ node->id = unit->box_id;
+ node->addr = unit->ctl;
+
if (parsed) {
type = search_uncore_discovery_type(unit->box_type);
if (!type) {
pr_info("A spurious uncore type %d is detected, "
"Disable the uncore type.\n",
unit->box_type);
+ kfree(node);
return;
}
+
+ uncore_find_add_unit(node, &type->units, &type->num_units);
+
/* Store the first box of each die */
if (!type->box_ctrl_die[die])
type->box_ctrl_die[die] = unit->ctl;
@@ -152,16 +215,18 @@ uncore_insert_box_info(struct uncore_unit_discovery *unit,

type = get_uncore_discovery_type(unit);
if (!type)
- return;
+ goto free_node;

box_offset = kcalloc(type->num_boxes + 1, sizeof(u64), GFP_KERNEL);
if (!box_offset)
- return;
+ goto free_node;

ids = kcalloc(type->num_boxes + 1, sizeof(unsigned int), GFP_KERNEL);
if (!ids)
goto free_box_offset;

+ uncore_find_add_unit(node, &type->units, &type->num_units);
+
/* Store generic information for the first box */
if (!type->num_boxes) {
type->box_ctrl = unit->ctl;
@@ -201,6 +266,8 @@ uncore_insert_box_info(struct uncore_unit_discovery *unit,
free_box_offset:
kfree(box_offset);

+free_node:
+ kfree(node);
}

static bool
@@ -339,8 +406,16 @@ bool intel_uncore_has_discovery_tables(int *ignore)
void intel_uncore_clear_discovery_tables(void)
{
struct intel_uncore_discovery_type *type, *next;
+ struct intel_uncore_discovery_unit *pos;
+ struct rb_node *node;

rbtree_postorder_for_each_entry_safe(type, next, &discovery_tables, node) {
+ while (!RB_EMPTY_ROOT(&type->units)) {
+ node = rb_first(&type->units);
+ pos = rb_entry(node, struct intel_uncore_discovery_unit, node);
+ rb_erase(node, &type->units);
+ kfree(pos);
+ }
kfree(type->box_ctrl_die);
kfree(type);
}
diff --git a/arch/x86/events/intel/uncore_discovery.h b/arch/x86/events/intel/uncore_discovery.h
index 22e769a81103..5190017aba51 100644
--- a/arch/x86/events/intel/uncore_discovery.h
+++ b/arch/x86/events/intel/uncore_discovery.h
@@ -113,17 +113,27 @@ struct uncore_unit_discovery {
};
};

+struct intel_uncore_discovery_unit {
+ struct rb_node node;
+ unsigned int pmu_idx; /* The idx of the corresponding PMU */
+ unsigned int id; /* Unit ID */
+ unsigned int die; /* Die ID */
+ u64 addr; /* Unit Control Address */
+};
+
struct intel_uncore_discovery_type {
struct rb_node node;
enum uncore_access_type access_type;
u64 box_ctrl; /* Unit ctrl addr of the first box */
u64 *box_ctrl_die; /* Unit ctrl addr of the first box of each die */
+ struct rb_root units; /* Unit ctrl addr for all units */
u16 type; /* Type ID of the uncore block */
u8 num_counters;
u8 counter_width;
u8 ctl_offset; /* Counter Control 0 offset */
u8 ctr_offset; /* Counter 0 offset */
u16 num_boxes; /* number of boxes for the uncore block */
+ u16 num_units; /* number of units */
unsigned int *ids; /* Box IDs */
u64 *box_offset; /* Box offset */
};
--
2.35.1