Index: sys/powerpc/powernv/platform_powernv.c
===================================================================
--- sys/powerpc/powernv/platform_powernv.c
+++ sys/powerpc/powernv/platform_powernv.c
@@ -483,16 +483,36 @@
 static struct cpu_group *
 powernv_smp_topo(platform_t plat)
 {
+	cpuset_t dom;
+	int corespdom, i, j;
+
 	if (mp_ncpus % smp_threads_per_core != 0) {
-		printf("WARNING: Irregular SMP topology. Performance may be "
-		     "suboptimal (%d threads, %d on first core)\n",
-		     mp_ncpus, smp_threads_per_core);
+		printf("%s: irregular SMP topology (%d threads, %d per core)\n",
+		    __func__, mp_ncpus, smp_threads_per_core);
 		return (smp_topo_none());
 	}
 
-	/* Don't do anything fancier for non-threaded SMP */
-	if (smp_threads_per_core == 1)
-		return (smp_topo_none());
+	corespdom = mp_ncpus / vm_ndomains;
+	if (mp_ncpus % vm_ndomains != 0 ||
+	    corespdom % smp_threads_per_core != 0) {
+		printf("%s: irregular NUMA topology\n", __func__);
+	} else if (vm_ndomains > 1) {
+		for (i = 0; i < vm_ndomains; i++) {
+			CPU_ZERO(&dom);
+			for (j = 0; j < corespdom; j++)
+				CPU_SET(i * corespdom + j, &dom);
+			if (CPU_CMP(&dom, &cpuset_domain[i]) != 0) {
+				printf("%s: non-contiguous NUMA domains\n",
+				    __func__);
+				break;
+			}
+		}
+		if (i == vm_ndomains) {
+			return (smp_topo_2level(CG_SHARE_L3,
+			    corespdom / smp_threads_per_core, CG_SHARE_L1,
+			    smp_threads_per_core, CG_FLAG_SMT));
+		}
+	}
 
 	return (smp_topo_1level(CG_SHARE_L1, smp_threads_per_core,
 	    CG_FLAG_SMT));