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Add padding in list allocation #92914
Description
Since the Python memory allocator has granularity of 16 bytes, allocating 24 bytes does not save memory in comparison with allocating 32 bytes. One of changes in #82554 was to round the allocated size for list up to 4 items (16 bytes on 32-bit platform and 32 bytes of 64-bit platform). #87740 reverted this. Therefore, if you create an empty list, then extend it with 1 item two times, you will need two allocations, even if the first allocation has a space for yet one item (but list does not know about this).
>>> import sys
>>> a = []
>>> sys.getsizeof(a)
56
>>> a += [1]
>>> sys.getsizeof(a)
64
>>> a += [2]
>>> sys.getsizeof(a)
120
Activity
pythongh-92914: Always round up the size allocated for lists up to 16…
gh-92914: Round the allocated size for lists up to the even number (G…
pythongh-92914: Round the allocated size for lists up to the even num…
pythongh-92914: Round the allocated size for lists up to the even num…
gh-92914: Round the allocated size for lists up to the even number (G…
gh-92914: Round the allocated size for lists up to the even number (G…