5 releases (breaking)
0.5.0 | Aug 10, 2024 |
---|---|
0.4.0 | Jun 24, 2024 |
0.3.0 | Jan 26, 2024 |
0.2.0 | Nov 30, 2023 |
0.1.0 | Oct 29, 2023 |
#160 in Concurrency
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Simple periodic time slice scheduler
A simple multi-core scheduler that provides a trait to the application. This trait, if implemented for an application specific object, can be used to get periodic calls from the scheduler. The application trait object has to be registered to the scheduler to get the periodic calls.
Task methods of the scheduler trait are optional to implement, if one or more methods is not needed for a particular application object.
Restrictions
To keep things simple, the scheduler has a couple of restrictions:
- All task periods must be multiples of the smallest task period.
- All tasks run with the same OS priority. Therefore, the tasks won't interrupt each other.
- The order of execution of the tasks is undefined.
- The number of application objects that can be registered to the scheduler is compile time constant.
Supported platforms
- esp-idf-hal: ESP32 with IDF.
Cargo.toml
[dependencies]
timeslice = { version = "0.4", features = [ "hal-espidf", "meas" ] }
Example code
A simple usage example can look like this:
// Here we define the scheduler, its tasks and behavior.
timeslice::define_timeslice_sched! {
name: sched_main,
num_objs: 1,
tasks: {
{ name: task_10ms, period: 10 ms, cpu: 0, stack: 16 kiB },
{ name: task_50ms, period: 50 ms, cpu: 0, stack: 3 kiB },
{ name: task_100ms, period: 100 ms, cpu: 1, stack: 16 kiB },
}
}
// This structure belongs to your application. It contains application state.
struct MyThing {
// ...
}
impl MyThing {
fn new() -> Self {
Self {
// ...
}
}
}
// Implement the scheduler's tasks for your application.
impl sched_main::Ops for Box<MyThing> {
fn task_10ms(&self) {
// Called every 10 ms.
// ... Put your code here ...
}
fn task_50ms(&self) {
// Called every 50 ms.
// ... Put your code here ...
}
fn task_100ms(&self) {
// Called every 100 ms.
// ... Put your code here ...
}
}
fn main() {
// Initialize the application.
use std::sync::Arc;
let thing = Arc::new(Box::new(MyThing::new()));
// Initialize the scheduler and register your application.
let obj = Arc::clone(&thing);
sched_main::init([obj]);
// ...
}
See the documentation for more complex examples.
Backend selection
One backend has to be selected via feature
flags. The following backends are available:
hal-espidf
: Useesp-idf-hal
andesp-idf-svc
hal backend. Select this, if you use an ESP microcontroller.hal-dummy
: Backend for testing only. It does nothing. You should never select it.
Only one of the hal backend feature
flags can be selected.
esp-idf-hal and esp-idf-svc versions
The hal-espidf
backend depends on the following crates:
esp-idf-hal = "0.44"
esp-idf-svc = "0.49"
Features
meas
: If themeas
feature is enabled, then functions for run time measurements will be enabled. If this feature flag is not given, then the run time measurement functions will be empty dummies.
Internals
ESP-IDF implementation details
On hal-espidf
each task runs as a std::thread
that is pinned to the specified CPU core. The threads wait for a trigger signal from a periodic ESP timer. On triggering, the trait methods are executed, if the time slice is due.
Memory safety
This crate does not use unsafe
code.
License
Copyright 2023-2024 Michael Büsch m@bues.ch
Licensed under the Apache License version 2.0 or the MIT license, at your option.
SPDX-License-Identifier: Apache-2.0 OR MIT
Dependencies
~0–6MB
~35K SLoC