Adjust the way we number CPUs on x86 so that we attempt to "group" all

logical CPUs in a package.  We do this by numbering the non-boot CPUs
by starting with the first CPU whose APIC ID is after the boot CPU and
wrapping back around to APIC ID 0 if needed rather than always starting
at APIC ID 0.  While here, adjust the cpu_mp_announce() routine to list
CPUs based on the mapping established by assign_cpu_ids() rather than
making assumptions about the algorithm assign_cpu_ids() uses.

MFC after:	1 month

1 files changed, 29 insertions, 21 deletions

diff --git a/sys/amd64/amd64/mp_machdep.c b/sys/amd64/amd64/mp_machdep.c
index 59e3e9b..a45b398 100644
--- a/sys/amd64/amd64/mp_machdep.c
+++ b/sys/amd64/amd64/mp_machdep.c
@@ -354,8 +354,6 @@ cpu_mp_start(void)
 	} else
 		KASSERT(boot_cpu_id == PCPU_GET(apic_id),
 		    ("BSP's APIC ID doesn't match boot_cpu_id"));
-	cpu_apic_ids[0] = boot_cpu_id;
-	apic_cpuids[boot_cpu_id] = 0;
 
 	/* Setup the initial logical CPUs info. */
 	logical_cpus = logical_cpus_mask = 0;
@@ -418,28 +416,30 @@ cpu_mp_start(void)
 void
 cpu_mp_announce(void)
 {
-	int i, x;
 	const char *hyperthread;
+	int i;
 
-	/* List CPUs */
+	/* List active CPUs first. */
 	printf(" cpu0 (BSP): APIC ID: %2d\n", boot_cpu_id);
-	for (i = 1, x = 0; x <= MAX_APIC_ID; x++) {
-		if (!cpu_info[x].cpu_present || cpu_info[x].cpu_bsp)
+	for (i = 1; i < mp_ncpus; i++) {
+		if (cpu_info[cpu_apic_ids[i]].cpu_hyperthread)
+			hyperthread = "/HT";
+		else
+			hyperthread = "";
+		printf(" cpu%d (AP%s): APIC ID: %2d\n", i, hyperthread,
+		    cpu_apic_ids[i]);
+	}
+
+	/* List disabled CPUs last. */
+	for (i = 0; i <= MAX_APIC_ID; i++) {
+		if (!cpu_info[i].cpu_present || !cpu_info[i].cpu_disabled)
 			continue;
-		if (cpu_info[x].cpu_hyperthread) {
+		if (cpu_info[i].cpu_hyperthread)
 			hyperthread = "/HT";
-		} else {
+		else
 			hyperthread = "";
-		}
-		if (cpu_info[x].cpu_disabled)
-			printf("  cpu (AP%s): APIC ID: %2d (disabled)\n",
-			    hyperthread, x);
-		else {
-			KASSERT(i < mp_ncpus,
-			    ("mp_ncpus and actual cpus are out of whack"));
-			printf(" cpu%d (AP%s): APIC ID: %2d\n", i++,
-			    hyperthread, x);
-		}
+		printf("  cpu (AP%s): APIC ID: %2d (disabled)\n", hyperthread,
+		    i);
 	}
 }
 
@@ -693,11 +693,19 @@ assign_cpu_ids(void)
 
 	/*
 	 * Assign CPU IDs to local APIC IDs and disable any CPUs
-	 * beyond MAXCPU.  CPU 0 has already been assigned to the BSP,
-	 * so we only have to assign IDs for APs.
+	 * beyond MAXCPU.  CPU 0 is always assigned to the BSP.
+	 *
+	 * To minimize confusion for userland, we attempt to number
+	 * CPUs such that all threads and cores in a package are
+	 * grouped together.  For now we assume that the BSP is always
+	 * the first thread in a package and just start adding APs
+	 * starting with the BSP's APIC ID.
 	 */
 	mp_ncpus = 1;
-	for (i = 0; i <= MAX_APIC_ID; i++) {
+	cpu_apic_ids[0] = boot_cpu_id;
+	apic_cpuids[boot_cpu_id] = 0;
+	for (i = boot_cpu_id + 1; i != boot_cpu_id;
+	     i == MAX_APIC_ID ? i = 0 : i++) {
 		if (!cpu_info[i].cpu_present || cpu_info[i].cpu_bsp ||
 		    cpu_info[i].cpu_disabled)
 			continue;