Struct StreamPriorityScheduler 

pub struct StreamPriorityScheduler { /* private fields */ }

A stream-level priority scheduler for multiplexed network streams.

Scheduling Policies

Use SpsSchedulingPolicy to select the algorithm per call or batch.

Example

use ipfrs_network::stream_priority_scheduler::{
    StreamPriorityScheduler, SpsSchedulingPolicy, SpsSchedulerConfig,
};

let mut scheduler = StreamPriorityScheduler::new(SpsSchedulerConfig::default());
scheduler.add_stream(1, 100, 10).unwrap();
scheduler.add_stream(2, 50,  5).unwrap();
scheduler.enqueue_bytes(1, 4096).unwrap();
scheduler.enqueue_bytes(2, 2048).unwrap();

let result = scheduler.schedule_next(&SpsSchedulingPolicy::StrictPriority);
assert_eq!(result.map(|(id, _)| id), Some(1));

Implementations

impl StreamPriorityScheduler

pub fn new(config: SpsSchedulerConfig) -> Self

Create a new scheduler with the supplied configuration.

pub fn add_stream( &mut self, id: SpsStreamId, priority: u32, weight: u32, ) -> Result<(), SpsError>

Register a new stream.

Errors

Returns SpsError::MaxStreamsReached if config.max_streams is exceeded, or SpsError::DuplicateStream if the id is already registered.

pub fn remove_stream(&mut self, id: SpsStreamId) -> Result<SpsStream, SpsError>

Remove a stream and all its pending data from the scheduler.

Errors

Returns SpsError::StreamNotFound if the id is not registered.

pub fn block_stream(&mut self, id: SpsStreamId) -> Result<(), SpsError>

Block a stream — it will be skipped during scheduling.

Errors

Returns SpsError::StreamNotFound if the id is not registered.

pub fn unblock_stream(&mut self, id: SpsStreamId) -> Result<(), SpsError>

Unblock a previously blocked stream.

Errors

Returns SpsError::StreamNotFound if the id is not registered.

pub fn enqueue_bytes( &mut self, stream_id: SpsStreamId, bytes: u64, ) -> Result<(), SpsError>

Add bytes of pending data to a stream’s queue.

Also inserts the stream into the appropriate priority queue if it was previously empty.

Errors

Returns SpsError::StreamNotFound if the id is not registered.

pub fn schedule_next( &mut self, policy: &SpsSchedulingPolicy, ) -> Option<(SpsStreamId, u64)>

Schedule the next stream according to policy.

Returns Some((stream_id, bytes_to_send)) where bytes_to_send is the number of bytes that should be dispatched this round (bounded by config.quantum_bytes for non-strict policies).

Returns None if there are no eligible streams.

pub fn schedule_batch( &mut self, policy: &SpsSchedulingPolicy, n: usize, ) -> Vec<(SpsStreamId, u64)>

Schedule a batch of up to n streams.

Each element of the returned Vec is (stream_id, bytes_to_send).

Errors (returned via empty vec)

If n == 0 the returned vec is empty.

pub fn run_drr_round(&mut self) -> Vec<(SpsStreamId, u64)>

Run one or more complete Deficit Round Robin rounds.

Each eligible stream receives a quantum of config.quantum_bytes added to its deficit counter. Streams transmit until their deficit is exhausted. The number of rounds is controlled by config.deficit_rounds.

Returns a list of (stream_id, bytes_to_send) decisions from this round.

pub fn compute_fairness(&self) -> f64

Compute Jain’s fairness index over all streams’ bytes_sent.

Returns a value in [0.0, 1.0] where 1.0 is perfectly fair. Returns 1.0 if there are fewer than two streams.

pub fn scheduler_stats(&mut self) -> SpsSchedulerStats

Return a snapshot of current scheduler statistics.

pub fn get_stream(&self, id: SpsStreamId) -> Option<&SpsStream>

Return a reference to a stream, or None.

pub fn get_stream_mut(&mut self, id: SpsStreamId) -> Option<&mut SpsStream>

Return a mutable reference to a stream, or None.

pub fn set_deadline( &mut self, id: SpsStreamId, deadline: u64, ) -> Result<(), SpsError>

Set the deadline for EDF scheduling on a stream.

Smaller values are scheduled earlier.

pub fn set_htb_params( &mut self, id: SpsStreamId, rate: u64, burst: u64, ) -> Result<(), SpsError>

Configure HTB token-bucket parameters for a stream.

pub fn htb_refill(&mut self, ticks: u64)

Refill HTB token buckets for all streams by ticks time units.

pub fn tick(&self) -> u64

Return the current tick counter.

pub fn stream_count(&self) -> usize

Return the number of currently registered streams.

pub fn eligible_count(&self) -> usize

Return the number of eligible (non-blocked, non-empty) streams.

pub fn drain_stream(&mut self, id: SpsStreamId) -> Result<u64, SpsError>

Drain all pending bytes from a stream without scheduling it.

Useful for flow-control / back-pressure scenarios.

pub fn update_priority( &mut self, id: SpsStreamId, new_priority: u32, ) -> Result<(), SpsError>

Update the priority of a stream.

This moves the stream to the new priority queue if it currently has data.