diff --git a/tools/funclatency.py b/tools/funclatency.py
index fe06d1b..3f08a7e 100755
--- a/tools/funclatency.py
+++ b/tools/funclatency.py
@@ -35,6 +35,7 @@
     ./funclatency c:read            # time the read() C library function
     ./funclatency -u vfs_read       # time vfs_read(), in microseconds
     ./funclatency -m do_nanosleep   # time do_nanosleep(), in milliseconds
+    ./funclatency -i 2 -d 10 c:open # output every 2 seconds, for duration 10s
     ./funclatency -mTi 5 vfs_read   # output every 5 seconds, with timestamps
     ./funclatency -p 181 vfs_read   # time process 181 only
     ./funclatency 'vfs_fstat*'      # time both vfs_fstat() and vfs_fstatat()
@@ -47,8 +48,10 @@
     epilog=examples)
 parser.add_argument("-p", "--pid", type=int,
     help="trace this PID only")
-parser.add_argument("-i", "--interval", default=99999999,
-    help="summary interval, seconds")
+parser.add_argument("-i", "--interval", type=int,
+    help="summary interval, in seconds")
+parser.add_argument("-d", "--duration", type=int,
+    help="total duration of trace, in seconds")
 parser.add_argument("-T", "--timestamp", action="store_true",
     help="include timestamp on output")
 parser.add_argument("-u", "--microseconds", action="store_true",
@@ -66,6 +69,10 @@
 parser.add_argument("--ebpf", action="store_true",
     help=argparse.SUPPRESS)
 args = parser.parse_args()
+if args.duration and not args.interval:
+    args.interval = args.duration
+if not args.interval:
+    args.interval = 99999999
 
 def bail(error):
     print("Error: " + error)
@@ -226,14 +233,18 @@
         return "%s [%d]" % (BPF.sym(key[0], key[1]), key[1])
 
 exiting = 0 if args.interval else 1
+seconds = 0
 dist = b.get_table("dist")
 while (1):
     try:
-        sleep(int(args.interval))
+        sleep(args.interval)
+        seconds += args.interval
     except KeyboardInterrupt:
         exiting = 1
         # as cleanup can take many seconds, trap Ctrl-C:
         signal.signal(signal.SIGINT, signal_ignore)
+    if args.duration and seconds >= args.duration:
+        exiting = 1
 
     print()
     if args.timestamp: