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classification
Title: concurrent.futures.ThreadPoolExecutor: tasks in queue not marked as done
Type: behavior Stage:
Components: Versions: Python 3.6, Python 3.5
process
Status: open Resolution:
Dependencies: Superseder:
Assigned To: Nosy List: pyfm
Priority: normal Keywords: patch

Created on 2016-11-09 16:05 by pyfm, last changed 2022-04-11 14:58 by admin.

Files
File name Uploaded Description Edit
thread.py.patch pyfm, 2016-11-09 16:05 Proposal of a patch
Messages (1)
msg280410 - (view) Author: pyfm (pyfm) Date: 2016-11-09 16:05 
Hi,

I just realized that the ThreadPoolExecutor's workers do not call task_done() on the work_queue from which they took their task.
Or is there a reason for not calling task_done that I am missing?

Calling task_done decrements the queue's unfinished_tasks counter which could be used to improve the reuse of idle threads (see bquinlan's comment, Lib/concurrent/futures/thread.py:l124).

I am thinking of something like
if self._work_queue.unfinished_tasks > len(self._threads) and len(self._threads) < self._max_workers:

One could still construct cases in which threads are created unnecessarily but it should improve the situation in most cases.

(proposed patch is based on Python-3.6.0b3)
History
Date User Action Args
2022-04-11 14:58:39adminsetgithub: 72836
2016-11-09 16:05:49pyfmcreate