perf bench numa: Fixup discontiguous/sparse numa nodes

Certain systems are designed to have sparse/discontiguous nodes.  On
such systems, 'perf bench numa' hangs, shows wrong number of nodes and
shows values for non-existent nodes. Handle this by only taking nodes
that are exposed by kernel to userspace.

Signed-off-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1edbcd353c009e109e93d78f2f46381930c340fe.1511368645.git.sathnaga@linux.vnet.ibm.com
Signed-off-by: Balamuruhan S <bala24@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 51 insertions, 5 deletions

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index d95fdcc26f4b..944070e98a2c 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -216,6 +216,47 @@ static const char * const numa_usage[] = {
         NULL
 };
 
+/*
+ * To get number of numa nodes present.
+ */
+static int nr_numa_nodes(void)
+{
+        int i, nr_nodes = 0;
+
+        for (i = 0; i < g->p.nr_nodes; i++) {
+                if (numa_bitmask_isbitset(numa_nodes_ptr, i))
+                        nr_nodes++;
+        }
+
+        return nr_nodes;
+}
+
+/*
+ * To check if given numa node is present.
+ */
+static int is_node_present(int node)
+{
+        return numa_bitmask_isbitset(numa_nodes_ptr, node);
+}
+
+/*
+ * To check given numa node has cpus.
+ */
+static bool node_has_cpus(int node)
+{
+        struct bitmask *cpu = numa_allocate_cpumask();
+        unsigned int i;
+
+        if (cpu && !numa_node_to_cpus(node, cpu)) {
+                for (i = 0; i < cpu->size; i++) {
+                        if (numa_bitmask_isbitset(cpu, i))
+                                return true;
+                }
+        }
+
+        return false; /* lets fall back to nocpus safely */
+}
+
 static cpu_set_t bind_to_cpu(int target_cpu)
 {
         cpu_set_t orig_mask, mask;
@@ -244,12 +285,12 @@ static cpu_set_t bind_to_cpu(int target_cpu)
 
 static cpu_set_t bind_to_node(int target_node)
 {
-        int cpus_per_node = g->p.nr_cpus/g->p.nr_nodes;
+        int cpus_per_node = g->p.nr_cpus / nr_numa_nodes();
         cpu_set_t orig_mask, mask;
         int cpu;
         int ret;
 
-        BUG_ON(cpus_per_node*g->p.nr_nodes != g->p.nr_cpus);
+        BUG_ON(cpus_per_node * nr_numa_nodes() != g->p.nr_cpus);
         BUG_ON(!cpus_per_node);
 
         ret = sched_getaffinity(0, sizeof(orig_mask), &orig_mask);
@@ -649,7 +690,7 @@ static int parse_setup_node_list(void)
                         int i;
 
                         for (i = 0; i < mul; i++) {
-                                if (t >= g->p.nr_tasks) {
+                                if (t >= g->p.nr_tasks || !node_has_cpus(bind_node)) {
                                         printf("\n# NOTE: ignoring bind NODEs starting at NODE#%d\n", bind_node);
                                         goto out;
                                 }
@@ -964,6 +1005,8 @@ static void calc_convergence(double runtime_ns_max, double *convergence)
         sum = 0;
 
         for (node = 0; node < g->p.nr_nodes; node++) {
+                if (!is_node_present(node))
+                        continue;
                 nr = nodes[node];
                 nr_min = min(nr, nr_min);
                 nr_max = max(nr, nr_max);
@@ -984,8 +1027,11 @@ static void calc_convergence(double runtime_ns_max, double *convergence)
         process_groups = 0;
 
         for (node = 0; node < g->p.nr_nodes; node++) {
-                int processes = count_node_processes(node);
+                int processes;
 
+                if (!is_node_present(node))
+                        continue;
+                processes = count_node_processes(node);
                 nr = nodes[node];
                 tprintf(" %2d/%-2d", nr, processes);
 
@@ -1291,7 +1337,7 @@ static void print_summary(void)
 
         printf("\n ###\n");
         printf(" # %d %s will execute (on %d nodes, %d CPUs):\n",
-                g->p.nr_tasks, g->p.nr_tasks == 1 ? "task" : "tasks", g->p.nr_nodes, g->p.nr_cpus);
+                g->p.nr_tasks, g->p.nr_tasks == 1 ? "task" : "tasks", nr_numa_nodes(), g->p.nr_cpus);
         printf(" #      %5dx %5ldMB global  shared mem operations\n",
                         g->p.nr_loops, g->p.bytes_global/1024/1024);
         printf(" #      %5dx %5ldMB process shared mem operations\n",