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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年04月27日 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年04月27日 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
-----------------------------------+--------------+---------------