bevy/crates/bevy_tasks/README.md

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# Bevy Tasks
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A refreshingly simple task executor for bevy. :)
This is a simple threadpool with minimal dependencies. The main usecase is a scoped fork-join, i.e. spawning tasks from
Cleanup of Markdown Files and add CI Checking (#1463) I have run the VSCode Extension [markdownlint](https://marketplace.visualstudio.com/items?itemName=DavidAnson.vscode-markdownlint) on all Markdown Files in the Repo. The provided Rules are documented here: https://github.com/DavidAnson/markdownlint/blob/v0.23.1/doc/Rules.md Rules I didn't follow/fix: * MD024/no-duplicate-heading * Changelog: Here Heading will always repeat. * Examples Readme: Platform-specific documentation should be symmetrical. * MD025/single-title * MD026/no-trailing-punctuation * Caused by the ! in "Hello, World!". * MD033/no-inline-html * The plugins_guidlines file does need HTML, so the shown badges aren't downscaled too much. * ~~MD036/no-emphasis-as-heading:~~ * ~~This Warning only Appears in the Github Issue Templates and can be ignored.~~ * ~~MD041/first-line-heading~~ * ~~Only appears in the Readme for the AlienCake example Assets, which is unimportant.~~ --- I also sorted the Examples in the Readme and Cargo.toml in this order/Priority: * Topic/Folder * Introductionary Examples * Alphabetical Order The explanation for each case, where it isn't Alphabetical : * Diagnostics * log_diagnostics: The usage of inbuild Diagnostics is more important than creating your own. * ECS (Entity Component System) * ecs_guide: The guide should be read, before diving into other Features. * Reflection * reflection: Basic Explanation should be read, before more advanced Topics. * WASM Examples * hello_wasm: It's "Hello, World!".
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a single thread and having that thread await the completion of those tasks. This is intended specifically for
[`bevy`][bevy] as a lighter alternative to [`rayon`][rayon] for this specific usecase. There are also utilities for
Cleanup of Markdown Files and add CI Checking (#1463) I have run the VSCode Extension [markdownlint](https://marketplace.visualstudio.com/items?itemName=DavidAnson.vscode-markdownlint) on all Markdown Files in the Repo. The provided Rules are documented here: https://github.com/DavidAnson/markdownlint/blob/v0.23.1/doc/Rules.md Rules I didn't follow/fix: * MD024/no-duplicate-heading * Changelog: Here Heading will always repeat. * Examples Readme: Platform-specific documentation should be symmetrical. * MD025/single-title * MD026/no-trailing-punctuation * Caused by the ! in "Hello, World!". * MD033/no-inline-html * The plugins_guidlines file does need HTML, so the shown badges aren't downscaled too much. * ~~MD036/no-emphasis-as-heading:~~ * ~~This Warning only Appears in the Github Issue Templates and can be ignored.~~ * ~~MD041/first-line-heading~~ * ~~Only appears in the Readme for the AlienCake example Assets, which is unimportant.~~ --- I also sorted the Examples in the Readme and Cargo.toml in this order/Priority: * Topic/Folder * Introductionary Examples * Alphabetical Order The explanation for each case, where it isn't Alphabetical : * Diagnostics * log_diagnostics: The usage of inbuild Diagnostics is more important than creating your own. * ECS (Entity Component System) * ecs_guide: The guide should be read, before diving into other Features. * Reflection * reflection: Basic Explanation should be read, before more advanced Topics. * WASM Examples * hello_wasm: It's "Hello, World!".
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generating the tasks from a slice of data. This library is intended for games and makes no attempt to ensure fairness
or ordering of spawned tasks.
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It is based on [`async-executor`][async-executor], a lightweight executor that allows the end user to manage their own threads.
`async-executor` is based on async-task, a core piece of async-std.
## Usage
In order to be able to optimize task execution in multi-threaded environments,
bevy provides three different thread pools via which tasks of different kinds can be spawned.
(The same API is used in single-threaded environments, even if execution is limited to a single thread.
This currently applies to Wasm targets.)
The determining factor for what kind of work should go in each pool is latency requirements:
* For CPU-intensive work (tasks that generally spin until completion) we have a standard
[`ComputeTaskPool`] and an [`AsyncComputeTaskPool`]. Work that does not need to be completed to
present the next frame should go to the [`AsyncComputeTaskPool`].
* For IO-intensive work (tasks that spend very little time in a "woken" state) we have an
[`IoTaskPool`] whose tasks are expected to complete very quickly. Generally speaking, they should just
await receiving data from somewhere (i.e. disk) and signal other systems when the data is ready
for consumption. (likely via channels)
[bevy]: https://bevyengine.org
[rayon]: https://github.com/rayon-rs/rayon
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[async-executor]: https://github.com/stjepang/async-executor