tests/thread: Allow thread tests to pass with the native emitter.

dpgeorge · dpgeorge · commit 526493b4a093 · 2025-07-13T22:49:52.000+10:00
The native emitter will not release/bounce the GIL when running code, so
if it runs tight loops then no other threads get a chance to run (if the
GIL is enabled).  So for the thread tests, explicitly include a call to
`time.sleep(0)` (or equivalent) to bounce the GIL and give other threads a
chance to run.

For some tests (eg `thread_coop.py`) the whole point of the test is to test
that the GIL is correctly bounced.  So for those cases for the use of the
bytecode emitter for the busy functions.

Signed-off-by: Damien George &lt;damien@micropython.org&gt;
diff --git a/tests/thread/mutate_bytearray.py b/tests/thread/mutate_bytearray.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 # the shared bytearray
@@ -36,7 +37,7 @@ def th(n, lo, hi):
 
 # busy wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 
 # check bytearray has correct contents
 print(len(ba))
diff --git a/tests/thread/mutate_dict.py b/tests/thread/mutate_dict.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 # the shared dict
@@ -36,9 +37,9 @@ def th(n, lo, hi):
 for i in range(n_thread):
     _thread.start_new_thread(th, (30, i * 300, (i + 1) * 300))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 
 # check dict has correct contents
 print(sorted(di.items()))
diff --git a/tests/thread/mutate_instance.py b/tests/thread/mutate_instance.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 
@@ -38,9 +39,9 @@ def th(n, lo, hi):
 for i in range(n_thread):
     _thread.start_new_thread(th, (n_repeat, i * n_range, (i + 1) * n_range))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 
 # check user instance has correct contents
 print(user.a, user.b, user.c)
diff --git a/tests/thread/mutate_list.py b/tests/thread/mutate_list.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 # the shared list
@@ -37,9 +38,9 @@ def th(n, lo, hi):
 for i in range(n_thread):
     _thread.start_new_thread(th, (4, i * 60, (i + 1) * 60))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 
 # check list has correct contents
 li.sort()
diff --git a/tests/thread/mutate_set.py b/tests/thread/mutate_set.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 # the shared set
@@ -31,9 +32,9 @@ def th(n, lo, hi):
 for i in range(n_thread):
     _thread.start_new_thread(th, (50, i * 500, (i + 1) * 500))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 
 # check set has correct contents
 print(sorted(se))
diff --git a/tests/thread/stress_recurse.py b/tests/thread/stress_recurse.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 
@@ -22,7 +23,7 @@ def thread_entry():
 
 _thread.start_new_thread(thread_entry, ())
 
-# busy wait for thread to finish
+# wait for thread to finish
 while not finished:
-    pass
+    time.sleep(0)
 print("done")
diff --git a/tests/thread/stress_schedule.py b/tests/thread/stress_schedule.py
@@ -27,6 +27,8 @@ def task(x):
     n += 1
 
 
+# This function must always use the bytecode emitter so it bounces the GIL when running.
+@micropython.bytecode
 def thread():
     while thread_run:
         try:
@@ -46,7 +48,7 @@ def thread():
 # Wait up to 10 seconds for 10000 tasks to be scheduled.
 t = time.ticks_ms()
 while n < _NUM_TASKS and time.ticks_diff(time.ticks_ms(), t) < _TIMEOUT_MS:
-    pass
+    time.sleep(0)
 
 # Stop all threads.
 thread_run = False
diff --git a/tests/thread/thread_coop.py b/tests/thread/thread_coop.py
@@ -7,6 +7,7 @@
 import _thread
 import sys
 from time import ticks_ms, ticks_diff, sleep_ms
+import micropython
 
 
 done = False
@@ -21,6 +22,8 @@
     MAX_DELTA = 100
 
 
+# This function must always use the bytecode emitter so the VM can bounce the GIL when running.
+@micropython.bytecode
 def busy_thread():
     while not done:
         pass
diff --git a/tests/thread/thread_exc1.py b/tests/thread/thread_exc1.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 
@@ -32,7 +33,7 @@ def thread_entry():
         except OSError:
             pass
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 print("done")
diff --git a/tests/thread/thread_gc1.py b/tests/thread/thread_gc1.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import gc
 import _thread
 
@@ -42,8 +43,8 @@ def thread_entry(n):
 thread_entry(10)
 n_thread += 1
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 
 print(n_correct == n_finished)
diff --git a/tests/thread/thread_ident1.py b/tests/thread/thread_ident1.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 
@@ -27,6 +28,6 @@ def thread_entry():
 new_tid = _thread.start_new_thread(thread_entry, ())
 
 while not finished:
-    pass
+    time.sleep(0)
 
 print("done", type(new_tid) == int, new_tid == tid)
diff --git a/tests/thread/thread_lock3.py b/tests/thread/thread_lock3.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 lock = _thread.allocate_lock()
@@ -24,6 +25,6 @@ def thread_entry(idx):
 for i in range(n_thread):
     _thread.start_new_thread(thread_entry, (i,))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
diff --git a/tests/thread/thread_shared1.py b/tests/thread/thread_shared1.py
@@ -2,6 +2,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 
@@ -38,7 +39,7 @@ def thread_entry(n, tup):
 thread_entry(100, tup)
 n_thread += 1
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 print(tup)
diff --git a/tests/thread/thread_shared2.py b/tests/thread/thread_shared2.py
@@ -3,6 +3,7 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+import time
 import _thread
 
 
@@ -29,7 +30,7 @@ def thread_entry(n, lst, idx):
 for i in range(n_thread):
     _thread.start_new_thread(thread_entry, ((i + 1) * 10, lst, i))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 print(lst)
diff --git a/tests/thread/thread_stacksize1.py b/tests/thread/thread_stacksize1.py
@@ -3,6 +3,7 @@
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
 import sys
+import time
 import _thread
 
 # different implementations have different minimum sizes
@@ -49,7 +50,7 @@ def thread_entry():
 # reset stack size to default (for subsequent scripts on baremetal)
 _thread.stack_size()
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(0)
 print("done")
diff --git a/tests/thread/thread_stdin.py b/tests/thread/thread_stdin.py
@@ -5,6 +5,7 @@
 # This is a regression test for https://github.com/micropython/micropython/issues/15230
 # on rp2, but doubles as a general property to test across all ports.
 import sys
+import time
 import _thread
 
 try:
@@ -38,7 +39,7 @@ def is_done(self):
 # have run yet. The actual delay is <20ms but spinning here instead of
 # sleep(0.1) means the test can run on MP builds without float support.
 while not thread_waiter.is_done():
-    pass
+    time.sleep(0)
 
 # The background thread should have completed its wait by now.
 print(thread_waiter.is_done())
