Struct SPMCBuffer

pub struct SPMCBuffer<T: Send + Sync> { /* private fields */ }

A single-producer multiple-consumer buffer, useful for thread-safe data sharing in scenarios where triple buffering won’t cut it.

Triple buffering is an extremely efficient synchronization protocol when a producer thread wants to constantly update a value that is visible by a single consumer thread. However, it is not safe to use in the presence of multiple consumers, because a consumer thread can no longer assume that it is the only thread having access to the read buffer and discard said read buffer at will.

Reference counting techniques can be used to build a variant of triple buffering which works for multiple consumers, remains provably wait-free if one uses two buffers per consumer, and degrades gracefully when a smaller amount of buffers is used as long as consumers frequently fetch updates from the producer. I call the resulting synchronization primitive an SPMC buffer.

Implementations

impl<T: Clone + Send + Sync> SPMCBuffer<T>

pub fn new(read_buffers: usize, initial: T) -> Self

Initialize an SPMC buffer with a certain amount of read buffers (which roughly determines how many readers can be accessing the structure at a slow pace before the writer starts to block).

impl<T: Default + Send + Sync> SPMCBuffer<T>

pub fn with_default(read_buffers: usize) -> Self

Like “new”, but uses default-constructed values of type T instead of cloning a user-provided initial value of this type.

impl<T: Send + Sync> SPMCBuffer<T>

pub fn split(self) -> (SPMCBufferInput<T>, SPMCBufferOutput<T>)

Extract input and output of the SPMC buffer

Trait Implementations

impl<T: Clone + Send + Sync> Clone for SPMCBuffer<T>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug + Send + Sync> Debug for SPMCBuffer<T>

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

Formats the value using the given formatter.

impl<T: PartialEq + Send + Sync> PartialEq for SPMCBuffer<T>

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.