[tip: perf/core] perf/x86/amd/uncore: Use Node ID to identify DF and UMC domains

[tip-bot2 for Sandipan Das]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     67d27727854def4a7e2b386429941f5c4741ccc4
Gitweb:        https://git.kernel.org/tip/67d27727854def4a7e2b386429941f5c4741ccc4
Author:        Sandipan Das <sandipan.das@xxxxxxx>
AuthorDate:    Mon, 01 Jun 2026 17:43:05 +05:30
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Thu, 04 Jun 2026 11:38:38 +02:00

perf/x86/amd/uncore: Use Node ID to identify DF and UMC domains

For DF and UMC PMUs, a single context is shared across all CPUs that
are connected to the same Data Fabric (DF) instance. Currently, the
Package ID, which also happens to be the Socket ID, is used to identify
DF instances. This approach works for configurations having a single IO
Die (IOD) but fails in the following cases.
  * Older Zen 1 processors, where each chiplet has its own DF instance.
  * Any configurations with multiple DF instances or multiple IODs in
    the same package.

The correct way to identify DF instances is through the Node ID (not to
be confused with NUMA Node ID). This is available in ECX[7:0] of CPUID
leaf 0x8000001e and returned via topology_amd_node_id(). Hence, replace
usage of topology_logical_package_id() with topology_amd_node_id().

Fixes: 07888daa056e ("perf/x86/amd/uncore: Move discovery and registration")
Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://patch.msgid.link/e7a71a727c6a7b118c23d3e469929c538c4665aa.1780315832.git.sandipan.das@xxxxxxx
---
 arch/x86/events/amd/uncore.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index dd956cf..a0364ca 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -700,7 +700,7 @@ void amd_uncore_df_ctx_scan(struct amd_uncore *uncore, unsigned int cpu)
 	info.split.aux_data = 0;
 	info.split.num_pmcs = NUM_COUNTERS_NB;
 	info.split.gid = 0;
-	info.split.cid = topology_logical_package_id(cpu);
+	info.split.cid = topology_amd_node_id(cpu);
 
 	if (pmu_version >= 2) {
 		ebx.full = cpuid_ebx(EXT_PERFMON_DEBUG_FEATURES);
@@ -999,8 +999,8 @@ void amd_uncore_umc_ctx_scan(struct amd_uncore *uncore, unsigned int cpu)
 	cpuid(EXT_PERFMON_DEBUG_FEATURES, &eax, &ebx.full, &ecx, &edx);
 	info.split.aux_data = ecx;	/* stash active mask */
 	info.split.num_pmcs = ebx.split.num_umc_pmc;
-	info.split.gid = topology_logical_package_id(cpu);
-	info.split.cid = topology_logical_package_id(cpu);
+	info.split.gid = topology_amd_node_id(cpu);
+	info.split.cid = topology_amd_node_id(cpu);
 	*per_cpu_ptr(uncore->info, cpu) = info;
 }