Macro main 

macro_rules! main {
    ($about:expr) => { ... };
    ($about:expr, $opts:ty) => { ... };
}

The main() of a scheduler: the objects its build script left in OUT_DIR, loaded and run by cli(). The scheduler’s options are a clap::Args structure, each field named as the tunable it sets, a time in microseconds as the tunable in nanoseconds, and what else the scheduler adds to the loader is its Scheduler implementation:

#[derive(clap::Args)]
struct Opts {
    /// Scheduling slice duration in microseconds.
    #[clap(short = 's', long, default_value = "5000")]
    slice_us: u64,
}

impl scx_rustsched_loader::Scheduler for Opts {}

scx_rustsched_loader::main!("A minimal sched_ext scheduler written in Rust BPF", Opts);

An option that is not the tunable’s value as it stands, such as a list of CPUs that the scheduler takes as a mask, has a name of its own, and Scheduler::settings() sets the tunable from it:

impl scx_rustsched_loader::Scheduler for Opts {
    fn settings(
        &self,
        params: &mut scx_rustsched_loader::Params,
    ) -> scx_rustsched_loader::Result<()> {
        params.set("primary_cpus", &mask_of(&self.primary_domain)?)
    }
}

Every tunable of the scheduler has to be set by one or the other.