Issue #4688: Add a heuristic so that tuples and dicts containing only
untrackable objects are not tracked by the garbage collector. This can
reduce the size of collections and therefore the garbage collection overhead
on long-running programs, depending on their particular use of datatypes.
(trivia: this makes the "binary_trees" benchmark from the Computer Language
Shootout 40% faster)
diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
index 6e2ea41..e9af550 100644
--- a/Lib/test/test_gc.py
+++ b/Lib/test/test_gc.py
@@ -415,6 +415,37 @@
self.assertEqual(gc.get_referents(1, 'a', 4j), [])
+ def test_is_tracked(self):
+ # Atomic built-in types are not tracked, user-defined objects and
+ # mutable containers are.
+ # NOTE: types with special optimizations (e.g. tuple) have tests
+ # in their own test files instead.
+ self.assertFalse(gc.is_tracked(None))
+ self.assertFalse(gc.is_tracked(1))
+ self.assertFalse(gc.is_tracked(1.0))
+ self.assertFalse(gc.is_tracked(1.0 + 5.0j))
+ self.assertFalse(gc.is_tracked(True))
+ self.assertFalse(gc.is_tracked(False))
+ self.assertFalse(gc.is_tracked("a"))
+ self.assertFalse(gc.is_tracked(u"a"))
+ self.assertFalse(gc.is_tracked(bytearray("a")))
+ self.assertFalse(gc.is_tracked(type))
+ self.assertFalse(gc.is_tracked(int))
+ self.assertFalse(gc.is_tracked(object))
+ self.assertFalse(gc.is_tracked(object()))
+
+ class OldStyle:
+ pass
+ class NewStyle(object):
+ pass
+ self.assertTrue(gc.is_tracked(gc))
+ self.assertTrue(gc.is_tracked(OldStyle))
+ self.assertTrue(gc.is_tracked(OldStyle()))
+ self.assertTrue(gc.is_tracked(NewStyle))
+ self.assertTrue(gc.is_tracked(NewStyle()))
+ self.assertTrue(gc.is_tracked([]))
+ self.assertTrue(gc.is_tracked(set()))
+
def test_bug1055820b(self):
# Corresponds to temp2b.py in the bug report.