bpo-30919: shared memory allocation performance regression in multiprocessing #2708
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There is a huge regression in creating shared memory arenas in 3.x compared to 2.7. Python 2.7 created an anonymous memory mappping, while 3.x mmaps an actual file.
ftruncate
instead of actual writes to create a sparse file where supported.tmpfs
(or equivalent) rather than a persistent storage-backed directory.https://bugs.python.org/issue30919