ninja-build/ninja

CMake build doesn't enable the use of ppoll on platforms that support it

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#1821 opened on Jul 28, 2020

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help wanted

Description

On platforms that support it, configure.py enables the use of ppoll by defining USE_PPOLL. CMake build doesn't replicate this logic which means that Ninja built with CMake is always going to use the less efficient pselect.

Contributor guide

Tech stack
cpp
Domain
build system
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++CMakeplatform specific syscallsNinja build system
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate how configure.py detects ppoll support via platform checks. Look at CMakeLists.txt to identify where to add a similar check. Use cmake's check symbol exists or check cxx source compiles to test for ppoll availability. Define USE PPOLL in the CMake build to match configure.py's logic.