Struct RuntimeMetrics

pub struct RuntimeMetrics { /* private fields */ }

Available on crate features dep_tokio and std only.

Handle to the runtime’s metrics.

This handle is internally reference-counted and can be freely cloned. A RuntimeMetrics handle is obtained using the Runtime::metrics method.

Implementations

impl RuntimeMetrics

pub fn num_workers(&self) -> usize

Returns the number of worker threads used by the runtime.

The number of workers is set by configuring worker_threads on runtime::Builder. When using the current_thread runtime, the return value is always 1.

Examples

use tokio::runtime::Handle;

#[tokio::main]
async fn main() {
    let metrics = Handle::current().metrics();

    let n = metrics.num_workers();
    println!("Runtime is using {} workers", n);
}

pub fn num_alive_tasks(&self) -> usize

Returns the current number of alive tasks in the runtime.

This counter increases when a task is spawned and decreases when a task exits.

Examples

use tokio::runtime::Handle;

#[tokio::main]
async fn main() {
   let metrics = Handle::current().metrics();

    let n = metrics.num_alive_tasks();
    println!("Runtime has {} alive tasks", n);
}

pub fn global_queue_depth(&self) -> usize

Returns the number of tasks currently scheduled in the runtime’s global queue.

Tasks that are spawned or notified from a non-runtime thread are scheduled using the runtime’s global queue. This metric returns the current number of tasks pending in the global queue. As such, the returned value may increase or decrease as new tasks are scheduled and processed.

Examples

use tokio::runtime::Handle;

#[tokio::main]
async fn main() {
    let metrics = Handle::current().metrics();

    let n = metrics.global_queue_depth();
    println!("{} tasks currently pending in the runtime's global queue", n);
}

Trait Implementations

impl Clone for RuntimeMetrics

fn clone(&self) -> RuntimeMetrics

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RuntimeMetrics

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.