[Python-Dev] new buffer in python2.7 (original) (raw)
Antoine Pitrou solipsis at pitrou.net
Wed Oct 27 13:15:42 CEST 2010
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>Here are micro-benchmarks under 3.2:
> $ ./python -m timeit -s "x = b'x'*10000" "x[:100]" > 10000000 loops, best of 3: 0.134 usec per loop > $ ./python -m timeit -s "x = memoryview(b'x'*10000)" "x[:100]" > 10000000 loops, best of 3: 0.151 usec per loop That's weird. The greedy slice needs two memory allocations. One for the ByteArray object itself, one for its cargo. In total, more that 100 bytes. In contrast, creating the MemoryView object requires only one allocation of a few dozen bytes.
It's not a bytearray object, it's a bytes object. It requires only a single allocation since the data is allocated inline. The memoryview object must also call getbuffer() again on the original object.
Regards
Antoine.
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