Patches item #1605020, was opened at 2006-11-28 21:49
Message generated for change (Comment added) made by mklaas
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Category: Core (C code)
Group: Python 2.6
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Mike Klaas (mklaas)
Assigned to: Nobody/Anonymous (nobody)
Summary: Performance boost for array repeat
Initial Comment:
Copy in exponentially-increasing sized chunks when performing array repeat.
This enables fast initialization of large arrays. Performance is about an
order of magnitude increase for single-element arrays, and about two orders of
magnitude faster for single-element character arrays (see comments)
----------------------------------------------------------------------
>Comment By: Mike Klaas (mklaas)
Date: 2006-11-28 21:54
Message:
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Benchmarks on slightly-contended machine; before & after
[ python-trunk]$ python -m timeit -s "from array import array" "array('c',
'\0')*100000"
100 loops, best of 3: 4 msec per loop
[ python-trunk]$ ./python -m timeit -s "from array import array"
"array('c', '\0')*100000"
100000 loops, best of 3: 14.5 usec per loop
[ python-trunk]$ python -m timeit -s "from array import array" "array('i',
[0])*100000"
100 loops, best of 3: 3.42 msec per loop
[ python-trunk]$ ./python -m timeit -s "from array import array"
"array('i', [0])*100000"
1000 loops, best of 3: 517 usec per loop
[ python-trunk]$ python -m timeit -s "from array import array" "array('i',
[0,1,2,3])*100000"
100 loops, best of 3: 4.95 msec per loop
[ python-trunk]$ ./python -m timeit -s "from array import array"
"array('i', [0,1,2,3])*100000"
100 loops, best of 3: 2.55 msec per loop
[ python-trunk]$ python -m timeit -s "from array import array" "array('c',
'\0'*100)*1000"
10000 loops, best of 3: 46.6 usec per loop
[ python-trunk]$ ./python -m timeit -s "from array import array"
"array('c', '\0'*100)*1000"
100000 loops, best of 3: 19.6 usec per loop
[ python-trunk]$ python -m timeit -s "from array import array" "array('c',
'\0'*1000)*100"
10000 loops, best of 3: 22.8 usec per loop
[ python-trunk]$ ./python -m timeit -s "from array import array"
"array('c', '\0'*1000)*100"
10000 loops, best of 3: 20.7 usec per loop
----------------------------------------------------------------------
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