30.07.14 06:59, Serhiy Storchaka написав(ла):
30.07.14 02:45, antoine.pitrou написав(ла):
http://hg.python.org/cpython/rev/79a5fbe2c78f
changeset: 91935:79a5fbe2c78f
parent: 91933:fbd104359ef8
user: Antoine Pitrou <solip...@pitrou.net>
date: Tue Jul 29 19:41:11 2014 -0400
summary:
Issue #22003: When initialized from a bytes object, io.BytesIO() now
defers making a copy until it is mutated, improving performance and
memory use on some use cases.
Patch by David Wilson.
Did you compare this with issue #15381 [1]?
[1] http://bugs.python.org/issue15381
Using microbenchmark from issue22003:
$ cat i.py
import io
word = b'word'
line = (word * int(79/len(word))) + b'\n'
ar = line * int((4 * 1048576) / len(line))
def readlines():
return len(list(io.BytesIO(ar)))
print('lines: %s' % (readlines(),))
$ ./python -m timeit -s 'import i' 'i.readlines()'
Before patch: 10 loops, best of 3: 46.9 msec per loop
After issue22003 patch: 10 loops, best of 3: 36.4 msec per loop
After issue15381 patch: 10 loops, best of 3: 27.6 msec per loop
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