[New-bugs-announce] [issue26359] CPython build options for out-of-the box performance

[Alecsandru Patrascu]

New submission from Alecsandru Patrascu:

Hello,

This is Alecsandru from the Dynamic Scripting Languages Optimization Team at Intel Corporation. I would like to submit a patch as a response to the discussion thread opened in Python-Dev (https://mail.python.org/pipermail/python-dev/2016-February/143215.html), regarding the way CPython is built, mainly the options that are available to the programmers. Analyzing the CPython ecosystem we can see that there are a lot of users that just download the sources and hit the commands "./configure", "make" and "make install" once and then continue using it with their Python scripts. One of the problems with this workflow it that the users do not benefit from the entire optimization features that are existing in the build system, such as PGO and LTO.

Therefore, I propose a workflow, like the following. Assume some work has to be done into the CPython interpreter, a developer can do the following steps:
A. Implementation and debugging phase. 
    1. The command "./configure PYDIST=debug" is ran once. It will enable the Py_DEBUG, -O0 and -g flags
    2. The command "make" is ran once or multiple times
    
B. Testing the implementation from step A, in a pre-release environment
    1. The command "./configure PYDIST=devel" is ran once. It will disable the Py_DEBUG flags and will enable the -O3 and -g flags, and it is just like the current implementation in CPython
    2. The command "make" is ran once or multiple times

C. For any other CPython usage, for example distributing the interpreter, installing it inside an operating system, or just the majority of users who are not CPython developers and only want to compile it once and use it as-is:
    1. The command "./configure" is ran once. Alternatively, the command  "./configure PYDIST=release" can be used. It will disable all debugging functionality, enable the -O3 flag and will enable PGO and LTO.
    2. The command "make" is ran once
    
Thank you,
Alecsandru

----------
components: Build
files: cpython2_pgo_default-v01.patch
keywords: patch
messages: 260271
nosy: alecsandru.patrascu
priority: normal
severity: normal
status: open
title: CPython build options for out-of-the box performance
type: performance
versions: Python 2.7, Python 3.5, Python 3.6
Added file: http://bugs.python.org/file41918/cpython2_pgo_default-v01.patch

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<http://bugs.python.org/issue26359>
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