diff --git a/tools/task_plots/iplot_tasks.py b/tools/task_plots/iplot_tasks.py
index c6f44dcf9d60338e9f738ce235e3e1a16327f498..dcac3ffe319b12d2a0ccf977faecaa05aa5d809a 100755
--- a/tools/task_plots/iplot_tasks.py
+++ b/tools/task_plots/iplot_tasks.py
@@ -402,7 +402,7 @@ data = data[1:, :]
 # Exit if no data.
 if data.size == 0:
     print(("# Rank ", rank, " has no tasks"))
-    os.exit(1)
+    sys.exit(1)
 
 start_t = float(tic_step)
 data[:, ticcol] -= start_t