diff --git a/Makefile b/Makefile
index dfb1a71..29933f3 100644
--- a/Makefile
+++ b/Makefile
@@ -4,19 +4,34 @@ ifeq ($(shell uname), Darwin)
 	argp:=-largp -pagezero_size 10000 -image_base 100000000
 endif
 
-all: LuaJIT/Makefile
-	cd ./LuaJIT && make -j
-	$(CC) main.c -O3 -c -o main.o -I ./LuaJIT/src
-	$(CC) main.o -lpthread ${argp} ./LuaJIT/src/libluajit.a -lm -ldl -o bench
+ifdef BENCH_DURATION
+	DURATION = -DBENCH_DURATION=$(BENCH_DURATION)
+endif
+
+ifndef LUAJIT_PATH
+	LUAJIT_PATH = ./LuaJIT
+endif
+
+LUAJIT_A = $(LUAJIT_PATH)/src/libluajit.a
+
+all: $(LUAJIT_PATH)/src/libluajit.a
+	$(CC) main.c $(DURATION) -O3 -c -o main.o -I $(LUAJIT_PATH)/src
+	$(CC) main.o -lpthread ${argp} $^ -lm -ldl -o bench
+
+$(LUAJIT_A): $(LUAJIT_PATH)/Makefile
+	make -C $(LUAJIT_PATH) -j
 
 LuaJIT/Makefile:
 	git submodule update --init --recursive
 
 clean:
-	cd ./LuaJIT && make clean
 	rm bench main.o
 
 distclean:
 	rm -rf LuaJIT
 	mkdir LuaJIT
 	rm bench main.o
+
+run: bench
+	@echo "<benchmark>:<total runs>:<ops/s>"
+	@ls *.lua | while read f; do echo -n "$$f:"; ./bench $$f; done
diff --git a/main.c b/main.c
index 3573f7f..fc838d3 100644
--- a/main.c
+++ b/main.c
@@ -9,6 +9,8 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <argp.h>
+#include <sys/param.h>
+#include <string.h>
 
 #include "lua.h"
 #include "lualib.h"
@@ -17,35 +19,47 @@
 typedef struct {
 	uint64_t  ctr;
 	char     *file;
-	double    start_ns;
+	uint64_t  start_ns;
+	uint64_t  end_ns;
 } lua_task;
 
+/* Benchmark execution duration in seconds. */
+#ifndef BENCH_DURATION
+# define BENCH_DURATION 10
+#endif
+
+#define TIMESPEC_NS(t) ((t).tv_sec * 1e9 + (t).tv_nsec)
+
 void *wrapper(void *arg) {
 	lua_task *task = (lua_task*)arg;
+	struct timespec start_time;
 	struct timespec cur_time;
-	double start_time_ns = task->start_ns;
 	uint64_t ctr = 0;
 
+	int status = clock_gettime(CLOCK_MONOTONIC, &start_time);
+
+	if (status != 0) {
+		fprintf(stderr, "clock_gettime failed: %s\n", strerror (errno));
+		exit(1);
+	}
+
+	uint64_t cur_time_ns = TIMESPEC_NS (start_time);
+	uint64_t stop_time_ns = TIMESPEC_NS (start_time) + BENCH_DURATION * 1e9;
+
 	lua_State *L;
 	L = luaL_newstate();
 	luaL_openlibs(L);
 
-	int status = luaL_loadfile(L, task->file);
-    	if (status) {
-        	fprintf(stderr, "Couldn't load file: %s\n", lua_tostring(L, -1));
-        	exit(1);
-    	}
+	status = luaL_loadfile(L, task->file);
+	if (status) {
+		fprintf(stderr, "Couldn't load file: %s\n", lua_tostring(L, -1));
+		exit(1);
+	}
 
         int cb_ref = luaL_ref(L, LUA_REGISTRYINDEX);
 
-	do {
-		clock_gettime(CLOCK_MONOTONIC, &cur_time);
-
-		double cur_time_ns = cur_time.tv_sec * 1e9 + cur_time.tv_nsec;
-		if (start_time_ns + 10 * 1e9 < cur_time_ns) {
-			break;
-		}
 
+	do {
 		lua_rawgeti(L, LUA_REGISTRYINDEX, cb_ref);
 		int result = lua_pcall(L, 0, 0, 0);
     		if (result) {
@@ -54,10 +68,18 @@ void *wrapper(void *arg) {
     		}
 
 		ctr++;
+		status = clock_gettime(CLOCK_MONOTONIC, &cur_time);
+		if (status != 0) {
+			fprintf(stderr, "clock_gettime failed: %s\n", strerror (errno));
+			exit(1);
+		}
 
-	} while(1);
+		cur_time_ns = TIMESPEC_NS (cur_time);
+	} while (stop_time_ns > cur_time_ns);;
 
 	task->ctr = ctr;
+	task->start_ns = TIMESPEC_NS (start_time);
+	task->end_ns = cur_time_ns;
 
 	return NULL;
 }
@@ -80,7 +102,7 @@ static char doc[] =
 static char args_doc[] = "file1";
 
 static struct argp_option options[] = {
-  {"concurency",  'c', "concurency", 0, "Number of threads" },
+  {"concurrency",  'c', "concurrency", 0, "Number of threads" },
   { 0 }
 };
 
@@ -122,28 +144,63 @@ int main(int argc, char *argv[]) {
     	size_t len;
     	struct stat s;
 	uint64_t total = 0;
-	struct timespec start_time;
 
   	cmd_line_options arguments = (cmd_line_options){.file_name = "", .q = 8, .c = 1};
-  	argp_parse (&argp, argc, argv, 0, 0, &arguments);
+	int ret = argp_parse (&argp, argc, argv, 0, 0, &arguments);
+
+	if (ret != 0) {
+		fprintf (stderr, "Unexpected error while parsing command line arguments: %s\n",
+			 strerror (ret));
+		return 1;
+	}
 	
 	int nthreads = arguments.c;
 	threads = malloc(nthreads * sizeof(pthread_t));
 	tasks = malloc(nthreads * sizeof(lua_task));
 
-	clock_gettime(CLOCK_MONOTONIC, &start_time);
-	double start_time_ns = start_time.tv_sec * 1e9 +  start_time.tv_nsec;
+	if (threads == NULL || tasks == NULL) {
+		fprintf(stderr, "Unable to allocate memory: %s\n", strerror (errno));
+		return 2;
+	}
 
 	for (i = 0; i < nthreads; i++) {
-		tasks[i] = (lua_task){.file = arguments.file_name, .start_ns = start_time_ns};
-		pthread_create(&threads[i], NULL, wrapper, &tasks[i]);
+		tasks[i] = (lua_task){.file = arguments.file_name};
+		int ret = pthread_create(&threads[i], NULL, wrapper, &tasks[i]);
+
+		if (ret != 0) {
+			fprintf (stderr, "Cannot create thread(%d): %s\n", i,
+				 strerror (errno));
+			return 3;
+		}
 	}
 
+	uint64_t start_time_ns = 0;
+	uint64_t end_time_ns = 0;
+
   	for (i = 0; i < nthreads; i++) {
-    		pthread_join(threads[i], NULL);
+		int ret = pthread_join(threads[i], NULL);
+
+		if (ret != 0) {
+			fprintf (stderr, "Thread join failed(%d): %s\n", i,
+				 strerror (errno));
+			return 4;
+		}
+
 		total += tasks[i].ctr;
+		/* Select the earliest starting time and the latest end time. */
+		if (start_time_ns == 0) {
+			start_time_ns = tasks[i].start_ns;
+			end_time_ns = tasks[i].end_ns;
+		}
+		else {
+			start_time_ns = MIN (start_time_ns, tasks[i].start_ns);
+			end_time_ns = MAX (end_time_ns, tasks[i].end_ns);
+		}
   	}
 
-	fprintf(stderr, "Total times executed: %"PRId64"\n", total);
-	fprintf(stdout, "ops/s %.2f\n", (double)total / 10);
+	uint64_t duration = end_time_ns - start_time_ns;
+
+	printf("%"PRId64":%.4f\n", total, (double) total * 1e9 / duration);
+
+	return 0;
 }