I wrote a short microbenchmark allocating objects using my benchmark.py script.

It looks like the operation "(None,) * N" is slower with calloc-3.patch, but it's unclear how much times slower it is. I don't understand why only this operation has different speed.

Do you have ideas for other benchmarks?

Using the timeit module:

$ ./python.orig -m timeit '(None,) * 10**5'
1000 loops, best of 3: 357 usec per loop
$ ./python.calloc -m timeit '(None,) * 10**5'
1000 loops, best of 3: 698 usec per loop

But with different parameters, the difference is lower:

$ ./python.orig -m timeit -r 20 -n '1000' '(None,) * 10**5'
1000 loops, best of 20: 362 usec per loop
$ ./python.calloc -m timeit -r 20 -n '1000' '(None,) * 10**5'
1000 loops, best of 20: 392 usec per loop


Results of bench_alloc.py:

Common platform:
CFLAGS: -Wno-unused-result -Werror=declaration-after-statement -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes
CPU model: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz
Python unicode implementation: PEP 393
Timer info: namespace(adjustable=False, implementation='clock_gettime(CLOCK_MONOTONIC)', monotonic=True, resolution=1e-09)
Timer: time.perf_counter
SCM: hg revision=462470859e57+ branch=default date="2014-04-26 19:01 -0400"
Platform: Linux-3.13.8-200.fc20.x86_64-x86_64-with-fedora-20-Heisenbug
Bits: int=32, long=64, long long=64, size_t=64, void*=64

Platform of campaign orig:
Timer precision: 42 ns
Date: 2014-04-27 12:27:26
Python version: 3.5.0a0 (default:462470859e57, Apr 27 2014, 11:52:55) [GCC 4.8.2 20131212 (Red Hat 4.8.2-7)]

Platform of campaign calloc:
Timer precision: 45 ns
Date: 2014-04-27 12:29:10
Python version: 3.5.0a0 (default:462470859e57+, Apr 27 2014, 12:04:57) [GCC 4.8.2 20131212 (Red Hat 4.8.2-7)]

-----------------------------------+--------------+---------------
Tests                              |         orig |         calloc
-----------------------------------+--------------+---------------
object()                           |    61 ns (*) |          62 ns
b'A' * 10                          |    55 ns (*) |    51 ns (-7%)
b'A' * 10**3                       |    99 ns (*) |          94 ns
b'A' * 10**6                       |  37.5 us (*) |        36.6 us
'A' * 10                           |    62 ns (*) |    58 ns (-7%)
'A' * 10**3                        |   107 ns (*) |         104 ns
'A' * 10**6                        |    37 us (*) |        36.6 us
'A' * 10**8                        |  16.2 ms (*) |        16.4 ms
decode 10 null bytes from ASCII    |   253 ns (*) |         248 ns
decode 10**3 null bytes from ASCII |   359 ns (*) |         357 ns
decode 10**6 null bytes from ASCII |  78.8 us (*) |        78.7 us
decode 10**8 null bytes from ASCII |  26.2 ms (*) |        25.9 ms
(None,) * 10**0                    |    30 ns (*) |          30 ns
(None,) * 10**1                    |    78 ns (*) |          77 ns
(None,) * 10**2                    |   427 ns (*) |   460 ns (+8%)
(None,) * 10**3                    |   3.5 us (*) |   3.7 us (+6%)
(None,) * 10**4                    |  34.7 us (*) |  37.2 us (+7%)
(None,) * 10**5                    |   357 us (*) |   390 us (+9%)
(None,) * 10**6                    |  3.86 ms (*) | 4.43 ms (+15%)
(None,) * 10**7                    |  50.4 ms (*) |        50.3 ms
(None,) * 10**8                    |   505 ms (*) |         504 ms
([None] * 10)[1:-1]                |   121 ns (*) |         120 ns
([None] * 10**3)[1:-1]             |  3.57 us (*) |        3.57 us
([None] * 10**6)[1:-1]             |  4.61 ms (*) |        4.59 ms
([None] * 10**8)[1:-1]             |   585 ms (*) |         582 ms
-----------------------------------+--------------+---------------
Total                              | 1.19 sec (*) |       1.19 sec
-----------------------------------+--------------+---------------