[Python-checkins] cpython (3.5): Issue #26796: Don't configure the number of workers for default threadpool

Fri Oct 21 17:42:05 EDT 2016

https://hg.python.org/cpython/rev/785597e758a1
changeset: 104629:785597e758a1
branch: 3.5
parent: 104626:0b5e28042355
user: Yury Selivanov <yury at magic.io>
date: Fri Oct 21 17:40:42 2016 -0400
summary:
 Issue #26796: Don't configure the number of workers for default threadpool executor.
Initial patch by Hans Lawrenz.
files:
 Doc/library/asyncio-eventloop.rst | 7 +++++++
 Lib/asyncio/base_events.py | 5 +----
 Misc/NEWS | 4 ++++
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
--- a/Doc/library/asyncio-eventloop.rst
+++ b/Doc/library/asyncio-eventloop.rst
@@ -670,6 +670,13 @@
 
 This method is a :ref:`coroutine <coroutine>`.
 
+ .. versionchanged:: 3.5.3
+ :meth:`BaseEventLoop.run_in_executor` no longer configures the
+ ``max_workers`` of the thread pool executor it creates, instead
+ leaving it up to the thread pool executor
+ (:class:`~concurrent.futures.ThreadPoolExecutor`) to set the
+ default.
+
 .. method:: AbstractEventLoop.set_default_executor(executor)
 
 Set the default executor used by :meth:`run_in_executor`.
diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
--- a/Lib/asyncio/base_events.py
+++ b/Lib/asyncio/base_events.py
@@ -41,9 +41,6 @@
 __all__ = ['BaseEventLoop']
 
 
-# Argument for default thread pool executor creation.
-_MAX_WORKERS = 5
-
 # Minimum number of _scheduled timer handles before cleanup of
 # cancelled handles is performed.
 _MIN_SCHEDULED_TIMER_HANDLES = 100
@@ -616,7 +613,7 @@
 if executor is None:
 executor = self._default_executor
 if executor is None:
- executor = concurrent.futures.ThreadPoolExecutor(_MAX_WORKERS)
+ executor = concurrent.futures.ThreadPoolExecutor()
 self._default_executor = executor
 return futures.wrap_future(executor.submit(func, *args), loop=self)
 
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -402,6 +402,10 @@
 children are done.
 Patch by Johannes Ebke.
 
+- Issue #26796: Don't configure the number of workers for default 
+ threadpool executor.
+ Initial patch by Hans Lawrenz.
+
 IDLE
 ----
 
-- 
Repository URL: https://hg.python.org/cpython
