New submission from Bennie Swart <benniesw...@gmail.com>:
The concurrent.futures.ThreadPoolExecutor class, which is the default asyncio executor, introduced the _idle_semaphore field in version 3.8 in order to track idle threads so they can be reused before increasing the pool size unnecessarily. This semaphore counter becomes unbalanced when the thread pool is over-saturated, as can be seen in the file provided. This is due to workers always incrementing the count after finishing a job, whereas the executor only decrements the count if it is already greater than 0. This seems to be a logic bug unrelated to the running environment and introduced since python 3.8. ---------- components: asyncio files: bug.py messages: 394017 nosy: asvetlov, bennieswart, yselivanov priority: normal severity: normal status: open title: ThreadPoolExecutor unbalanced semaphore count type: behavior versions: Python 3.8 Added file: https://bugs.python.org/file50054/bug.py _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue44188> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
