diff --git a/client.c b/client.c
index 1a6839e..6e91ed5 100644
--- a/client.c
+++ b/client.c
@@ -500,8 +500,6 @@ jack_client_thread (void *arg)
 			break;
 		}
 
-		rdtscll (client->control->when_started);
-
 		if (client->pollfd[0].revents & ~POLLIN) {
 			jack_error ("engine has shut down socket; thread exiting");
 			if (client->on_shutdown) {
@@ -597,8 +595,6 @@ jack_client_thread (void *arg)
 			   effort.
 			*/
 
-			rdtscll (control->when_done);
-
 			write (client->graph_next_fd, &c, 1);
 		}
 	}
diff --git a/jack/internal.h b/jack/internal.h
index ef7d704..1f889f6 100644
--- a/jack/internal.h
+++ b/jack/internal.h
@@ -125,8 +125,6 @@ typedef volatile struct {
     volatile ClientType type;             /* w: engine r: engine and client */
     volatile char       active : 1;       /* w: engine r: engine and client */
     volatile char       dead : 1;         /* r/w: engine */
-    volatile unsigned long long  when_started;
-    volatile unsigned long long  when_done;
 
     /* callbacks */