only print usage errors on rank 0

perf-regression/margo-p2p-latency.c

@@ -26,7 +26,7 @@ struct options
     char* na_transport;
 };
 
-static void parse_args(int argc, char **argv, struct options *opts);
+static int parse_args(int argc, char **argv, struct options *opts);
 static void usage(void);
 static int run_benchmark(int iterations, hg_id_t id, ssg_member_id_t target, 
     ssg_group_id_t gid, margo_instance_id mid, double *measurement_array);
@@ -84,7 +84,13 @@ int main(int argc, char **argv)
     printf("Process %d of %d is on %s\n",
 	rank, nranks, processor_name);
 
-    parse_args(argc, argv, &g_opts);
+    ret = parse_args(argc, argv, &g_opts);
+    if(ret < 0)
+    {
+        if(rank == 0)
+            usage();
+        exit(EXIT_FAILURE);
+    }
 
     /* boilerplate ABT initialization steps */
     /****************************************/
@@ -228,7 +234,7 @@ int main(int argc, char **argv)
     return 0;
 }
 
-static void parse_args(int argc, char **argv, struct options *opts)
+static int parse_args(int argc, char **argv, struct options *opts)
 {
     int opt;
     int ret;
@@ -248,46 +254,36 @@ static void parse_args(int argc, char **argv, struct options *opts)
                 if(!opts->diag_file_name)
                 {
                     perror("strdup");
-                    exit(EXIT_FAILURE);
+                    return(-1);
                 }
                 break;
             case 'i':
                 ret = sscanf(optarg, "%d", &opts->iterations);
                 if(ret != 1)
-                {
-                    usage();
-                    exit(EXIT_FAILURE);
-                }
+                    return(-1);
                 break;
             case 't':
                 ret = sscanf(optarg, "%u,%u", &opts->mercury_timeout_client, &opts->mercury_timeout_server);
                 if(ret != 2)
-                {
-                    usage();
-                    exit(EXIT_FAILURE);
-                }
+                    return(-1);
                 break;
             case 'n':
                 opts->na_transport = strdup(optarg);
                 if(!opts->na_transport)
                 {
                     perror("strdup");
-                    exit(EXIT_FAILURE);
+                    return(-1);
                 }
                 break;
             default:
-                usage();
-                exit(EXIT_FAILURE);
+                return(-1);
         }
     }
 
     if(opts->iterations < 1 || !opts->na_transport)
-    {
-        usage();
-        exit(EXIT_FAILURE);
-    }
+        return(-1);
 
-    return;
+    return(0);
 }
 
 static void usage(void)