[Python-checkins] bpo-33505: Optimize asyncio.ensure_future by reordering if conditions (GH-6836)

Mon May 28 12:42:08 EDT 2018

https://github.com/python/cpython/commit/e549c4be5fb010f5faf12236af8faa720a1429be
commit: e549c4be5fb010f5faf12236af8faa720a1429be
branch: master
author: jimmylai <albert_chs at yahoo.com.tw>
committer: Yury Selivanov <yury at magic.io>
date: 2018年05月28日T12:42:05-04:00
summary:
bpo-33505: Optimize asyncio.ensure_future by reordering if conditions (GH-6836)
files:
A Misc/NEWS.d/next/Library/2018-05-14-18-05-35.bpo-33505.L8pAyt.rst
M Lib/asyncio/tasks.py

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 5df1af6642e4..4a9db2a3a05c 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -542,17 +542,17 @@ def ensure_future(coro_or_future, *, loop=None):
 
 If the argument is a Future, it is returned directly.
 """
- if futures.isfuture(coro_or_future):
- if loop is not None and loop is not futures._get_loop(coro_or_future):
- raise ValueError('loop argument must agree with Future')
- return coro_or_future
- elif coroutines.iscoroutine(coro_or_future):
+ if coroutines.iscoroutine(coro_or_future):
 if loop is None:
 loop = events.get_event_loop()
 task = loop.create_task(coro_or_future)
 if task._source_traceback:
 del task._source_traceback[-1]
 return task
+ elif futures.isfuture(coro_or_future):
+ if loop is not None and loop is not futures._get_loop(coro_or_future):
+ raise ValueError('loop argument must agree with Future')
+ return coro_or_future
 elif inspect.isawaitable(coro_or_future):
 return ensure_future(_wrap_awaitable(coro_or_future), loop=loop)
 else:
diff --git a/Misc/NEWS.d/next/Library/2018-05-14-18-05-35.bpo-33505.L8pAyt.rst b/Misc/NEWS.d/next/Library/2018-05-14-18-05-35.bpo-33505.L8pAyt.rst
new file mode 100644
index 000000000000..201b02781c18
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2018-05-14-18-05-35.bpo-33505.L8pAyt.rst
@@ -0,0 +1 @@
+Optimize asyncio.ensure_future() by reordering if checks: 1.17x faster.
