STINNER Victor added the comment: It looks like Windows supports also lazy initialization of memory pages initialized to zero.
According to my microbenchmark on Linux and Windows, only bytes(n) and bytearray(n) are really faster with use_calloc.patch. Most changes of use_calloc.patch are maybe useless since all bytes are initilized to zero, but just after that they are replaced with new bytes. Results of bench_alloc2.py on Windows 7: original vs calloc-4.patch+use_calloc.patch: Common platform: Timer: time.perf_counter Python unicode implementation: PEP 393 Bits: int=32, long=32, long long=64, size_t=32, void*=32 Platform: Windows-7-6.1.7601-SP1 CFLAGS: None Timer info: namespace(adjustable=False, implementation='QueryPerformanceCounter( )', monotonic=True, resolution=1e-08) Platform of campaign orig: SCM: hg revision=4b97092aa4bd branch=default date="2014-04-27 18:02 +0100" Date: 2014-04-28 09:35:30 Python version: 3.5.0a0 (default, Apr 28 2014, 09:33:30) [MSC v.1600 32 bit (Int el)] Timer precision: 4.47 us Platform of campaign calloc: SCM: hg revision=4f0aaa8804c6 tag=tip branch=default date="2014-04-28 09:27 +020 0" Date: 2014-04-28 09:37:37 Python version: 3.5.0a0 (default:4f0aaa8804c6, Apr 28 2014, 09:37:03) [MSC v.160 0 32 bit (Intel)] Timer precision: 4.44 us -----------------------+-------------+---------------- Tests | orig | calloc -----------------------+-------------+---------------- object() | 121 ns (*) | 109 ns (-10%) b'A' * 10 | 77 ns (*) | 79 ns b'A' * 10**3 | 159 ns (*) | 168 ns (+5%) b'A' * 10**6 | 428 us (*) | 415 us 'A' * 10 | 87 ns (*) | 89 ns 'A' * 10**3 | 175 ns (*) | 177 ns 'A' * 10**6 | 429 us (*) | 454 us (+6%) 'A' * 10**8 | 48.4 ms (*) | 49 ms (None,) * 10**0 | 49 ns (*) | 51 ns (None,) * 10**1 | 115 ns (*) | 99 ns (-14%) (None,) * 10**2 | 433 ns (*) | 422 ns (None,) * 10**3 | 3.58 us (*) | 3.57 us (None,) * 10**4 | 34.9 us (*) | 34.9 us (None,) * 10**5 | 347 us (*) | 351 us (None,) * 10**6 | 5.14 ms (*) | 4.85 ms (-6%) (None,) * 10**7 | 53.2 ms (*) | 50.2 ms (-6%) (None,) * 10**8 | 563 ms (*) | 515 ms (-9%) ([None] * 10)[1:-1] | 217 ns (*) | 217 ns ([None] * 10**3)[1:-1] | 3.89 us (*) | 3.92 us ([None] * 10**6)[1:-1] | 5.13 ms (*) | 5.17 ms ([None] * 10**8)[1:-1] | 634 ms (*) | 533 ms (-16%) bytes(10) | 193 ns (*) | 206 ns (+7%) bytes(10**3) | 266 ns (*) | 296 ns (+12%) bytes(10**6) | 414 us (*) | 3.89 us (-99%) bytes(10**8) | 44.2 ms (*) | 4.56 us (-100%) bytearray(10) | 229 ns (*) | 243 ns (+6%) bytearray(10**3) | 301 ns (*) | 330 ns (+10%) bytearray(10**6) | 421 us (*) | 3.89 us (-99%) bytearray(10**8) | 44.4 ms (*) | 4.56 us (-100%) -----------------------+-------------+---------------- Total | 1.4 sec (*) | 1.16 sec (-17%) -----------------------+-------------+---------------- ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue21233> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
