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	Concurrent accesses from multiple threads to the same `cell` object did not scale well in the free-threaded build. Use `_PyStackRef` and optimistically avoid locking to improve scaling. With the locks around cell reads gone, some of the free threading tests were prone to starvation: the readers were able to run in a tight loop and the writer threads weren't scheduled frequently enough to make timely progress. Adjust the tests to avoid this. Co-authored-by: Donghee Na <donghee.na@python.org>
		
			
				
	
	
		
			67 lines
		
	
	
	
		
			1.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			67 lines
		
	
	
	
		
			1.6 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
import unittest
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import threading
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from threading import Thread
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from unittest import TestCase
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import gc
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from test.support import threading_helper
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class MyObj:
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    pass
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@threading_helper.requires_working_threading()
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class TestGC(TestCase):
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    def test_get_objects(self):
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        event = threading.Event()
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        def gc_thread():
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            for i in range(100):
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                o = gc.get_objects()
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            event.set()
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        def mutator_thread():
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            while not event.is_set():
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                o1 = MyObj()
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                o2 = MyObj()
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                o3 = MyObj()
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                o4 = MyObj()
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        gcs = [Thread(target=gc_thread)]
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        mutators = [Thread(target=mutator_thread) for _ in range(4)]
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        with threading_helper.start_threads(gcs + mutators):
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            pass
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    def test_get_referrers(self):
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        NUM_GC = 2
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        NUM_MUTATORS = 4
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        b = threading.Barrier(NUM_GC + NUM_MUTATORS)
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        event = threading.Event()
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        obj = MyObj()
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        def gc_thread():
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            b.wait()
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            for i in range(100):
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                o = gc.get_referrers(obj)
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            event.set()
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        def mutator_thread():
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            b.wait()
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            while not event.is_set():
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                d1 = { "key": obj }
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                d2 = { "key": obj }
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                d3 = { "key": obj }
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                d4 = { "key": obj }
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        gcs = [Thread(target=gc_thread) for _ in range(NUM_GC)]
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        mutators = [Thread(target=mutator_thread) for _ in range(NUM_MUTATORS)]
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        with threading_helper.start_threads(gcs + mutators):
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            pass
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if __name__ == "__main__":
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    unittest.main()
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