diff --git a/tests/thread/stress_schedule.py b/tests/thread/stress_schedule.py
index c5a402b3a3..8be7f2d737 100644
--- a/tests/thread/stress_schedule.py
+++ b/tests/thread/stress_schedule.py
@@ -14,7 +14,11 @@ except AttributeError:
 
 gc.disable()
 
+_NUM_TASKS = 10000
+_TIMEOUT_MS = 10000
+
 n = 0  # How many times the task successfully ran.
+t = None  # Start time of test, assigned here to preallocate entry in globals dict.
 
 
 def task(x):
@@ -34,9 +38,6 @@ def thread():
 for i in range(8):
     _thread.start_new_thread(thread, ())
 
-_NUM_TASKS = const(10000)
-_TIMEOUT_MS = const(10000)
-
 # Wait up to 10 seconds for 10000 tasks to be scheduled.
 t = utime.ticks_ms()
 while n < _NUM_TASKS and utime.ticks_diff(utime.ticks_ms(), t) < _TIMEOUT_MS: