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49 lines
1.5 KiB
Python
49 lines
1.5 KiB
Python
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# Run by test_gc.
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from test import support
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import _testinternalcapi
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import gc
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import unittest
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class IncrementalGCTests(unittest.TestCase):
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# Use small increments to emulate longer running process in a shorter time
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@support.gc_threshold(200, 10)
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def test_incremental_gc_handles_fast_cycle_creation(self):
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class LinkedList:
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#Use slots to reduce number of implicit objects
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__slots__ = "next", "prev", "surprise"
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def __init__(self, next=None, prev=None):
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self.next = next
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if next is not None:
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next.prev = self
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self.prev = prev
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if prev is not None:
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prev.next = self
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def make_ll(depth):
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head = LinkedList()
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for i in range(depth):
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head = LinkedList(head, head.prev)
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return head
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head = make_ll(1000)
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assert(gc.isenabled())
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olds = []
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initial_heap_size = _testinternalcapi.get_tracked_heap_size()
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for i in range(20_000):
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newhead = make_ll(20)
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newhead.surprise = head
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olds.append(newhead)
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if len(olds) == 20:
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new_objects = _testinternalcapi.get_tracked_heap_size() - initial_heap_size
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self.assertLess(new_objects, 27_000, f"Heap growing. Reached limit after {i} iterations")
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del olds[:]
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if __name__ == "__main__":
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unittest.main()
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