Enum LoadBalancing 

#[non_exhaustive]
pub enum LoadBalancing {
    RoundRobin,
    LeastLoaded,
    IncomingCpu,
}

How the server distributes items between workers.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

RoundRobin

Items are sent to the workers in turn.

Workers whose runtime is blocked by a task are skipped while another worker is available.

LeastLoaded

Each item is sent to the less loaded of two randomly chosen workers.

A worker’s load is its runtime utilization, averaged over the last ~250 ms and not counting the time the runtime is blocked by a task. Workers whose utilization differs by less than 10% are compared by their open connections plus queued items. Workers whose runtime is blocked by a task are skipped while another worker is available.

IncomingCpu

Each connection is sent to the worker placed on the CPU that receives its network packets, unless that worker is busier than other workers.

The worker on the incoming CPU, or on an SMT sibling of it if no worker is placed on that CPU, is used if its utilization exceeds the LeastLoaded choice by at most 20% and its load by at most half plus 16. Otherwise, and for items without a known incoming CPU, it works like LeastLoaded.

The incoming CPU is the receive-side scaling (RSS) CPU of the connection on Windows, known for connections over network adapters with RSS, and the CPU that processed the connection’s last packet (SO_INCOMING_CPU) on Linux and Android. Requires worker affinity, see Affinity.

This is the default.

Trait Implementations

impl Clone for LoadBalancing

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for LoadBalancing

impl Debug for LoadBalancing

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

Formats the value using the given formatter.

impl Default for LoadBalancing

fn default() -> Self

Returns the “default value” for a type.

impl Eq for LoadBalancing

impl Hash for LoadBalancing

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LoadBalancing

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for LoadBalancing