Repository navigation
call_method(): call _PyObject_FastCall() rather than _PyObject_VaCallFunctionObjArgs() #73419
Description
| BPO | 29233 |
|---|---|
| Nosy | @vstinner, @serhiy-storchaka |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
Show more details
GitHub fields:
assignee = None
closed_at = <Date 2017-01-11.00:26:53.162>
created_at = <Date 2017-01-10.23:05:00.633>
labels = ['interpreter-core', '3.7', 'performance']
title = 'call_method(): call _PyObject_FastCall() rather than _PyObject_VaCallFunctionObjArgs()'
updated_at = <Date 2017-01-11.00:26:53.161>
user = 'https://github.com/vstinner'bugs.python.org fields:
activity = <Date 2017-01-11.00:26:53.161>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2017-01-11.00:26:53.162>
closer = 'vstinner'
components = ['Interpreter Core']
creation = <Date 2017-01-10.23:05:00.633>
creator = 'vstinner'
dependencies = []
files = []
hgrepos = []
issue_num = 29233
keywords = []
message_count = 3.0
messages = ['285165', '285166', '285167']
nosy_count = 3.0
nosy_names = ['vstinner', 'python-dev', 'serhiy.storchaka']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'performance'
url = 'https://bugs.python.org/issue29233'
versions = ['Python 3.7']
Activity
vstinner commentedon Jan 10, 2017
Recently, I modified call_method() and call_maybe() of Objects/typeobject.c to avoid the creation of a temporary tuple: replace Py_VaBuildValue()+PyObject_Call() with the new _PyObject_VaCallFunctionObjArgs().
But while working on the issue bpo-28870, I noticed that _PyObject_VaCallFunctionObjArgs() is not efficient and can be avoided. In typeobject.c, the number of arguments is hardcoded, so we don't need complex functions to compute the number of arguments and decide to allocate an array on the stack or on the heap.
python-dev commentedon Jan 10, 2017
New changeset b9404639a18c by Victor Stinner in branch 'default':
call_method() now uses _PyObject_FastCall()
https://hg.python.org/cpython/rev/b9404639a18c
vstinner commentedon Jan 10, 2017
Full commit message:
changeset: 106081:b9404639a18c
tag: tip
user: Victor Stinner <[email protected]>
date: Wed Jan 11 00:07:40 2017 +0100
files: Include/abstract.h Objects/abstract.c Objects/typeobject.c
description:
call_method() now uses _PyObject_FastCall()
Issue bpo-29233: Replace the inefficient _PyObject_VaCallFunctionObjArgs() with
_PyObject_FastCall() in call_method() and call_maybe().
Only a few functions call call_method() and call it with a fixed number of
arguments. Avoid the complex and expensive _PyObject_VaCallFunctionObjArgs()
function, replace it with an array allocated on the stack with the exact number
of argumlents.
It reduces the stack consumption, bytes per call, before => after:
test_python_call: 1168 => 1152 (-16 B)
test_python_getitem: 1344 => 1008 (-336 B)
test_python_iterator: 1568 => 1232 (-336 B)
Remove the _PyObject_VaCallFunctionObjArgs() function which became useless.
Rename it to object_vacall() and make it private.