tools/power turbostat: Fix --cpu-set 1 regression on HT systems

When the "--cpu-set" option limits turbostat to run on
a higher numbered HT sibling, it exits upon dividing by zero.

This is because the HT support handles higher numbered siblings
at the same time as lower numbered siblings.  But when that lower
number sibling is dis-allowed, the higher numbered sibling is
never processed.  The result is a time delta of 0, which results
in a divide by 0 for any of the "per-second" metrics.

Enhance the HT enumeration code to record all siblings (up to SMT4).
Consult this complete HT sibling list to determine when
to process an HT sibling, and when to skip it.

Fixes: a2b4d0f ("tools/power turbostat: Favor cpu# over core#")
Signed-off-by: Len Brown <len.brown@intel.com>

Author: lenb

tools/power/x86/turbostat/turbostat.c

@@ -2449,6 +2449,22 @@ int cpu_is_not_allowed(int cpu)
 
 #define PER_THREAD_PARAMS  struct thread_data *t, struct core_data *c, struct pkg_data *p
 
+int has_allowed_lower_ht_sibling(int cpu)
+{
+	int i;
+
+	for (i = 0; i <= cpus[cpu].ht_id; ++i) {
+		int sibling_cpu_id = cpus[cpu].ht_sibling_cpu_id[i];
+
+		if (sibling_cpu_id == cpu)
+			return 0;
+
+		if (!cpu_is_not_allowed(sibling_cpu_id))
+			return 1;
+	}
+	return 0;
+}
+
 int for_all_cpus(int (func) (struct thread_data *, struct core_data *, struct pkg_data *),
 		 struct thread_data *thread_base, struct core_data *core_base, struct pkg_data *pkg_base)
 {
@@ -2466,7 +2482,7 @@ int for_all_cpus(int (func) (struct thread_data *, struct core_data *, struct pk
 		if (cpu_is_not_allowed(cpu))
 			continue;
 
-		if (cpus[cpu].ht_id > 0)	/* skip HT sibling */
+		if (has_allowed_lower_ht_sibling(cpu))	/* skip HT sibling */
 			continue;
 
 		t = &thread_base[cpu];
@@ -2475,12 +2491,18 @@ int for_all_cpus(int (func) (struct thread_data *, struct core_data *, struct pk
 
 		retval |= func(t, c, p);
 
-		/* Handle HT sibling now */
+		/* Handle other HT siblings now */
 		int i;
 
-		for (i = MAX_HT_ID; i > 0; --i) {	/* ht_id 0 is self */
+		for (i = 0; i <= MAX_HT_ID; ++i) {
 			int sibling_cpu_id = cpus[cpu].ht_sibling_cpu_id[i];
 
+			if (sibling_cpu_id < 0)
+				break;
+
+			if (sibling_cpu_id == cpu)
+				continue;
+
 			if (cpu_is_not_allowed(sibling_cpu_id))
 				continue;
 
@@ -6178,11 +6200,11 @@ int set_thread_siblings(struct cpu_topology *thiscpu)
 	int cpu = thiscpu->cpu_id;
 	int offset = topo.max_cpu_num + 1;
 	size_t size;
-	int thread_id = 0;
+	int ht_id = 0;
 
 	thiscpu->put_ids = CPU_ALLOC((topo.max_cpu_num + 1));
 	if (thiscpu->ht_id < 0)
-		thiscpu->ht_id = thread_id++;
+		thiscpu->ht_id = 0;	/* first CPU in core */
 	if (!thiscpu->put_ids)
 		return -1;
 
@@ -6206,13 +6228,9 @@ int set_thread_siblings(struct cpu_topology *thiscpu)
 				sib_core = get_core_id(so);
 				if (sib_core == thiscpu->core_id) {
 					CPU_SET_S(so, size, thiscpu->put_ids);
-					if ((so != cpu) && (cpus[so].ht_id < 0)) {
-						cpus[so].ht_id = thread_id;
-						cpus[cpu].ht_sibling_cpu_id[thread_id] = so;
-						if (debug)
-							fprintf(stderr, "%s: cpu%d.ht_sibling_cpu_id[%d] = %d\n", __func__, cpu, thread_id, so);
-						thread_id += 1;
-					}
+					cpus[so].ht_id = ht_id;
+					cpus[cpu].ht_sibling_cpu_id[ht_id] = so;
+					ht_id += 1;
 				}
 			}
 		}
@@ -6245,7 +6263,7 @@ int for_all_cpus_2(int (func) (struct thread_data *, struct core_data *,
 		if (cpu_is_not_allowed(cpu))
 			continue;
 
-		if (cpus[cpu].ht_id > 0)	/* skip HT sibling */
+		if (has_allowed_lower_ht_sibling(cpu))	/* skip HT sibling */
 			continue;
 
 		t = &thread_base[cpu];
@@ -6260,9 +6278,15 @@ int for_all_cpus_2(int (func) (struct thread_data *, struct core_data *,
 		/* Handle HT sibling now */
 		int i;
 
-		for (i = MAX_HT_ID; i > 0; --i) {	/* ht_id 0 is self */
+		for (i = 0; i <= MAX_HT_ID; ++i) {
 			int sibling_cpu_id = cpus[cpu].ht_sibling_cpu_id[i];
 
+			if (sibling_cpu_id < 0)
+				break;
+
+			if (sibling_cpu_id == cpu)
+				continue;
+
 			if (cpu_is_not_allowed(sibling_cpu_id))
 				continue;
 
@@ -9517,6 +9541,8 @@ void topology_probe(bool startup)
 	cpu_present_setsize = CPU_ALLOC_SIZE((topo.max_cpu_num + 1));
 	CPU_ZERO_S(cpu_present_setsize, cpu_present_set);
 	for_all_proc_cpus(mark_cpu_present);
+	if (debug)
+		print_cpu_set("present set", cpu_present_set);
 
 	/*
 	 * Allocate and initialize cpu_possible_set
@@ -9527,6 +9553,8 @@ void topology_probe(bool startup)
 	cpu_possible_setsize = CPU_ALLOC_SIZE((topo.max_cpu_num + 1));
 	CPU_ZERO_S(cpu_possible_setsize, cpu_possible_set);
 	initialize_cpu_set_from_sysfs(cpu_possible_set, "/sys/devices/system/cpu", "possible");
+	if (debug)
+		print_cpu_set("possible set", cpu_possible_set);
 
 	/*
 	 * Allocate and initialize cpu_effective_set
@@ -9537,6 +9565,8 @@ void topology_probe(bool startup)
 	cpu_effective_setsize = CPU_ALLOC_SIZE((topo.max_cpu_num + 1));
 	CPU_ZERO_S(cpu_effective_setsize, cpu_effective_set);
 	update_effective_set(startup);
+	if (debug)
+		print_cpu_set("effective set", cpu_effective_set);
 
 	/*
 	 * Allocate and initialize cpu_allowed_set
@@ -9580,6 +9610,8 @@ void topology_probe(bool startup)
 
 		CPU_SET_S(i, cpu_allowed_setsize, cpu_allowed_set);
 	}
+	if (debug)
+		print_cpu_set("allowed set", cpu_allowed_set);
 
 	if (!CPU_COUNT_S(cpu_allowed_setsize, cpu_allowed_set))
 		err(-ENODEV, "No valid cpus found");
@@ -9683,12 +9715,18 @@ void topology_probe(bool startup)
 		return;
 
 	for (i = 0; i <= topo.max_cpu_num; ++i) {
+		int ht_id;
+
 		if (cpu_is_not_present(i))
 			continue;
 		fprintf(outf,
-			"cpu %d pkg %d die %d l3 %d node %d lnode %d core %d thread %d\n",
+			"cpu %d pkg %d die %d l3 %d node %d lnode %d core %d ht_id %d",
 			i, cpus[i].package_id, cpus[i].die_id, cpus[i].l3_id,
 			cpus[i].physical_node_id, cpus[i].logical_node_id, cpus[i].core_id, cpus[i].ht_id);
+		fprintf(outf, " siblings");
+		for (ht_id = 0; ht_id <= MAX_HT_ID; ++ht_id)
+			fprintf(outf, " %d", cpus[i].ht_sibling_cpu_id[ht_id]);
+		fprintf(outf, "\n");
 	}
 
 }
@@ -9829,6 +9867,8 @@ void topology_update(void)
 	topo.allowed_cores = 0;
 	topo.allowed_packages = 0;
 	for_all_cpus(update_topo, ODD_COUNTERS);
+	if (debug)
+		fprintf(stderr, "allowed_cpus %d allowed_cores %d allowed_packages %d\n", topo.allowed_cpus, topo.allowed_cores, topo.allowed_packages);
 }
 
 void setup_all_buffers(bool startup)