diff --git a/include/haproxy/cpu_topo.h b/include/haproxy/cpu_topo.h
index a48fee015..0e7243488 100644
--- a/include/haproxy/cpu_topo.h
+++ b/include/haproxy/cpu_topo.h
@@ -28,6 +28,9 @@ int cpu_detect_usable(void);
 /* detect the CPU topology based on info in /sys */
 int cpu_detect_topology(void);
 
+/* compose clusters */
+void cpu_compose_clusters(void);
+
 /* Detects CPUs that are bound to the current process. Returns the number of
  * CPUs detected or 0 if the detection failed.
  */
diff --git a/src/cpu_topo.c b/src/cpu_topo.c
index 9c405d786..0e5a49dd9 100644
--- a/src/cpu_topo.c
+++ b/src/cpu_topo.c
@@ -415,6 +415,54 @@ static int cpu_topo_get_maxcpus(void)
 	return abs_max;
 }
 
+/* This function is responsible for composing clusters based on existing info
+ * on the CPU topology.
+ */
+void cpu_compose_clusters(void)
+{
+	int cpu;
+	int curr_gid, prev_gid;
+	int curr_lid, prev_lid;
+
+	/* Now we'll sort CPUs by topology and assign cluster IDs to those that
+	 * don't yet have one, based on the die/pkg/llc.
+	 */
+	cpu_reorder_by_locality(ha_cpu_topo, cpu_topo_maxcpus);
+
+	prev_gid = prev_lid = -2; // make sure it cannot match even unassigned ones
+	curr_gid = curr_lid = -1;
+	for (cpu = 0; cpu <= cpu_topo_lastcpu; cpu++) {
+		/* renumber clusters and assign unassigned ones at the same
+		 * time. For this, we'll compare pkg/die/llc with the last
+		 * CPU's and verify if we need to create a new cluster ID.
+		 * Note that some platforms don't report cache. The locao value
+		 * is local to the pkg+node combination so that we reset it
+		 * when changing, contrary to the global one which grows.
+		 */
+		if (!cpu ||
+		    (ha_cpu_topo[cpu].pk_id != ha_cpu_topo[cpu-1].pk_id) ||
+		    (ha_cpu_topo[cpu].no_id != ha_cpu_topo[cpu-1].no_id)) {
+			curr_gid++;
+			curr_lid = 0;
+		}
+		else if (ha_cpu_topo[cpu].cl_gid != prev_gid ||
+			 ha_cpu_topo[cpu].ca_id[4] != ha_cpu_topo[cpu-1].ca_id[4] ||
+			 (ha_cpu_topo[cpu].ca_id[4] < 0 && // no l4 ? check L3
+			  ((ha_cpu_topo[cpu].ca_id[3] != ha_cpu_topo[cpu-1].ca_id[3]) ||
+			   (ha_cpu_topo[cpu].ca_id[3] < 0 && // no l3 ? check L2
+			    (ha_cpu_topo[cpu].ca_id[2] != ha_cpu_topo[cpu-1].ca_id[2]))))) {
+			curr_gid++;
+			curr_lid++;
+		}
+		prev_gid = ha_cpu_topo[cpu].cl_gid;
+		prev_lid = ha_cpu_topo[cpu].cl_lid;
+		ha_cpu_topo[cpu].cl_gid = curr_gid;
+		ha_cpu_topo[cpu].cl_lid = curr_lid;
+	}
+
+	cpu_reorder_by_index(ha_cpu_topo, cpu_topo_maxcpus);
+}
+
 /* CPU topology detection below, OS-specific */
 
 #if defined(__linux__)
diff --git a/src/haproxy.c b/src/haproxy.c
index 3beba0461..f09e87124 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2065,6 +2065,9 @@ static void step_init_2(int argc, char** argv)
 
 	/* Now detect how CPUs are arranged */
 	cpu_detect_topology();
+
+	/* compose clusters */
+	cpu_compose_clusters();
 #endif
 
 	/* detect the optimal thread-groups and nbthreads if not set */