Speed-up deque indexing by changing the deque block length to a power of two.
The division and modulo calculation in deque_item() can be compiled
to fast bitwise operations when the BLOCKLEN is a power of two.
Timing before:
~/cpython $ py -m timeit -r7 -s 'from collections import deque' -s 'd=deque(range(10))' 'd[5]'
10000000 loops, best of 7: 0.0627 usec per loop
Timing after:
~/cpython $ py -m timeit -r7 -s 'from collections import deque' -s 'd=deque(range(10))' 'd[5]'
10000000 loops, best of 7: 0.0581 usec per loop
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index a8487d2..e782b99 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -536,7 +536,7 @@
@support.cpython_only
def test_sizeof(self):
- BLOCKLEN = 62
+ BLOCKLEN = 64
basesize = support.calcobjsize('2P4nlP')
blocksize = struct.calcsize('2P%dP' % BLOCKLEN)
self.assertEqual(object.__sizeof__(deque()), basesize)