[issue24475] The docs never define what a pool "task" is
New submission from Zahari Dim:
See:
http://stackoverflow.com/questions/30943161/multiprocessing-pool-with-maxtas...
The documentation never makes clear what a "task" in the context of Pool.map. At best, it says:
"This method chops the iterable into a number of chunks which it submits to the process pool as separate tasks. The (approximate) size of these chunks can be specified by setting chunksize to a positive integer."
in the map documentation. However it does not say how this chunks are calculated by default, making the maxtasksperchild argument not very useful. The fact that a function evaluated by map is not a "task" should be much clearer in the documentation.
Also, in the examples, such as:
with multiprocessing.Pool(PROCESSES) as pool:
#
# Tests
#
TASKS = [(mul, (i, 7)) for i in range(10)] + \
[(plus, (i, 8)) for i in range(10)]
results = [pool.apply_async(calculate, t) for t in TASKS]
imap_it = pool.imap(calculatestar, TASKS)
imap_unordered_it = pool.imap_unordered(calculatestar, TASKS)
TASKS are not actually "tasks" but rather "task groups".
----------
assignee: docs@python
components: Documentation
messages: 245509
nosy: Zahari.Dim, docs@python
priority: normal
severity: normal
status: open
title: The docs never define what a pool "task" is
versions: Python 2.7, Python 3.2, Python 3.3, Python 3.4, Python 3.5, Python 3.6
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Python tracker
participants (5)
-
Daniel Neuberger
-
Davin Potts
-
Irit Katriel
-
Ned Deily
-
Zahari Dim