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Add doc comments for `QoSClass`
| -rw-r--r-- | crates/stdx/src/thread.rs | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/crates/stdx/src/thread.rs b/crates/stdx/src/thread.rs index 46d797bbb7..bbf0c6b82b 100644 --- a/crates/stdx/src/thread.rs +++ b/crates/stdx/src/thread.rs @@ -94,9 +94,116 @@ impl<T> fmt::Debug for JoinHandle<T> { #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)] // Please maintain order from least to most priority for the derived `Ord` impl. pub enum QoSClass { + // Documentation adapted from https://github.com/apple-oss-distributions/libpthread/blob/67e155c94093be9a204b69637d198eceff2c7c46/include/sys/qos.h#L55 + // + /// TLDR: invisible maintenance tasks + /// + /// Contract: + /// + /// * **You do not care about how long it takes for work to finish.** + /// * **You do not care about work being deferred temporarily.** + /// (e.g. if the device’s battery is in a critical state) + /// + /// Examples: + /// + /// * in a video editor: + /// creating periodic backups of project files + /// * in a browser: + /// cleaning up cached sites which have not been accessed in a long time + /// * in a collaborative word processor: + /// creating a searchable index of all documents + /// + /// Use this QoS class for background tasks + /// which the user did not initiate themselves + /// and which are invisible to the user. + /// It is expected that this work will take significant time to complete: + /// minutes or even hours. + /// + /// This QoS class provides the most energy and thermally-efficient execution possible. + /// All other work is prioritized over background tasks. Background, + + /// TLDR: tasks that don’t block using your app + /// + /// Contract: + /// + /// * **Your app remains useful even as the task is executing.** + /// + /// Examples: + /// + /// * in a video editor: + /// exporting a video to disk – + /// the user can still work on the timeline + /// * in a browser: + /// automatically extracting a downloaded zip file – + /// the user can still switch tabs + /// * in a collaborative word processor: + /// downloading images embedded in a document – + /// the user can still make edits + /// + /// Use this QoS class for tasks which + /// may or may not be initiated by the user, + /// but whose result is visible. + /// It is expected that this work will take a few seconds to a few minutes. + /// Typically your app will include a progress bar + /// for tasks using this class. + /// + /// This QoS class provides a balance between + /// performance, responsiveness and efficiency. Utility, + + /// TLDR: tasks that block using your app + /// + /// Contract: + /// + /// * **You need this work to complete + /// before the user can keep interacting with your app.** + /// * **Your work will not take more than a few seconds to complete.** + /// + /// Examples: + /// + /// * in a video editor: + /// opening a saved project + /// * in a browser: + /// loading a list of the user’s bookmarks and top sites + /// when a new tab is created + /// * in a collaborative word processor: + /// running a search on the document’s content + /// + /// Use this QoS class for tasks which were initiated by the user + /// and block the usage of your app while they are in progress. + /// It is expected that this work will take a few seconds or less to complete; + /// not long enough to cause the user to switch to something else. + /// Your app will likely indicate progress on these tasks + /// through the display of placeholder content or modals. + /// + /// This QoS class is not energy-efficient. + /// Rather, it provides responsiveness + /// by prioritizing work above other tasks on the system + /// except for critical user-interactive work. UserInitiated, + + /// TLDR: render loops and nothing else + /// + /// Contract: + /// + /// * **You absolutely need this work to complete immediately + /// or your app will appear to freeze.** + /// * **Your work will always complete virtually instantaneously.** + /// + /// Examples: + /// + /// * the main thread in a GUI application + /// * the update & render loop in a game + /// * a secondary thread which progresses an animation + /// + /// Use this QoS class for any work which, if delayed, + /// will make your user interface unresponsive. + /// It is expected that this work will be virtually instantaneous. + /// + /// This QoS class is not energy-efficient. + /// Specifying this class is a request to run with + /// nearly all available system CPU and I/O bandwidth even under contention. UserInteractive, } |