diff --git a/exercise4/wave_2d_parallel.c b/exercise4/wave_2d_parallel.c
index bffb5ef..bfe57b7 100644
--- a/exercise4/wave_2d_parallel.c
+++ b/exercise4/wave_2d_parallel.c
@@ -276,7 +276,18 @@ int main(int argc, char **argv) {
   // TASK: T2
   // Time your code
   // BEGIN: T2
+  if (world_rank == ROOT)
+    gettimeofday(&t_start, NULL);
+
   simulate();
+  // MPI_Barrier(MPI_COMM_WORLD); // TODO
+
+  if (world_rank == ROOT) {
+    gettimeofday(&t_end, NULL);
+
+    printf("Total elapsed time: %lf seconds\n",
+           WALLTIME(t_end) - WALLTIME(t_start));
+  }
   // END: T2
 
   // Clean up and shut down