diff --git a/presubmit_support.py b/presubmit_support.py
index 23cc5e427a..9baee8c5c0 100755
--- a/presubmit_support.py
+++ b/presubmit_support.py
@@ -478,7 +478,7 @@ class InputApi(object):
       else:
         assert issubclass(t.message, _PresubmitResult)
         tests.append(t)
-    if tests and parallel:
+    if len(tests) > 1 and parallel:
       pool = multiprocessing.Pool()
       # async recipe works around multiprocessing bug handling Ctrl-C
       msgs.extend(pool.map_async(CallCommand, tests).get(99999))