diff --git a/test/event/event_perf/event_perf.c b/test/event/event_perf/event_perf.c
index 2a4f8a2b0..bec2591a9 100644
--- a/test/event/event_perf/event_perf.c
+++ b/test/event/event_perf/event_perf.c
@@ -37,6 +37,7 @@
 #include "spdk/event.h"
 #include "spdk_internal/event.h"
 #include "spdk/log.h"
+#include "spdk/string.h"
 
 static uint64_t g_tsc_rate;
 static uint64_t g_tsc_us_rate;
@@ -153,7 +154,11 @@ main(int argc, char **argv)
 			opts.reactor_mask = optarg;
 			break;
 		case 't':
-			g_time_in_sec = atoi(optarg);
+			g_time_in_sec = spdk_strtol(optarg, 10);
+			if (g_time_in_sec < 0) {
+				fprintf(stderr, "Invalid run time\n");
+				return g_time_in_sec;
+			}
 			break;
 		default:
 			usage(argv[0]);
diff --git a/test/event/reactor/reactor.c b/test/event/reactor/reactor.c
index d79f94baa..051b1aed5 100644
--- a/test/event/reactor/reactor.c
+++ b/test/event/reactor/reactor.c
@@ -34,6 +34,7 @@
 #include "spdk/stdinc.h"
 
 #include "spdk/event.h"
+#include "spdk/string.h"
 #include "spdk/thread.h"
 
 static int g_time_in_sec;
@@ -123,7 +124,7 @@ main(int argc, char **argv)
 	while ((op = getopt(argc, argv, "t:")) != -1) {
 		switch (op) {
 		case 't':
-			g_time_in_sec = atoi(optarg);
+			g_time_in_sec = spdk_strtol(optarg, 10);
 			break;
 		default:
 			usage(argv[0]);
@@ -131,7 +132,7 @@ main(int argc, char **argv)
 		}
 	}
 
-	if (!g_time_in_sec) {
+	if (g_time_in_sec <= 0) {
 		usage(argv[0]);
 		exit(1);
 	}
diff --git a/test/event/reactor_perf/reactor_perf.c b/test/event/reactor_perf/reactor_perf.c
index 357f9038a..8783b48f8 100644
--- a/test/event/reactor_perf/reactor_perf.c
+++ b/test/event/reactor_perf/reactor_perf.c
@@ -35,6 +35,7 @@
 
 #include "spdk/env.h"
 #include "spdk/event.h"
+#include "spdk/string.h"
 #include "spdk/thread.h"
 
 static int g_time_in_sec;
@@ -102,6 +103,7 @@ main(int argc, char **argv)
 	struct spdk_app_opts opts;
 	int op;
 	int rc;
+	long int val;
 
 	spdk_app_opts_init(&opts);
 	opts.name = "reactor_perf";
@@ -111,15 +113,24 @@ main(int argc, char **argv)
 	g_queue_depth = 1;
 
 	while ((op = getopt(argc, argv, "d:q:t:")) != -1) {
+		if (op == '?') {
+			usage(argv[0]);
+			exit(1);
+		}
+		val = spdk_strtol(optarg, 10);
+		if (val < 0) {
+			fprintf(stderr, "Converting a string to integer failed\n");
+			exit(1);
+		}
 		switch (op) {
 		case 'd':
-			opts.max_delay_us = atoi(optarg);
+			opts.max_delay_us = (uint64_t)val;
 			break;
 		case 'q':
-			g_queue_depth = atoi(optarg);
+			g_queue_depth = val;
 			break;
 		case 't':
-			g_time_in_sec = atoi(optarg);
+			g_time_in_sec = val;
 			break;
 		default:
 			usage(argv[0]);