Module budget 

Task Budget Enforcement

Implements task budget enforcement to ensure Ring 0 latency guarantees are met. Each operation has a time budget, and exceeding it triggers metrics/alerts. Ring 1 background tasks cooperatively yield when Ring 0 has pending work or when their budget is exhausted.

Budget Constants

Ring	Operation	Budget	Notes
0	Single event	500ns	p99 latency target
0	Event batch	5μs	Up to 10 events
0	State lookup	200ns	Fast path
0	Window trigger	10μs	Aggregation emission
1	Background chunk	1ms	Cooperative yielding
1	Checkpoint prep	10ms	Async operation
1	WAL flush	100μs	Group commit

Usage

use laminar_core::budget::TaskBudget;

// Ring 0: Track single event processing
fn process_event(event: &Event) {
    let _budget = TaskBudget::ring0_event();
    // Process event - metrics recorded automatically on drop
    process(event);
}

// Ring 1: Cooperative yielding
fn process_background_work(&mut self) -> YieldReason {
    let budget = TaskBudget::ring1_chunk();

    while !budget.exceeded() {
        if self.ring0_has_pending() {
            return YieldReason::Ring0Priority;
        }
        // Process work...
    }

    YieldReason::BudgetExceeded
}

Metrics

The module tracks:

• Task duration histograms (per task type, per ring)
• Budget violation counts
• Amount exceeded (for capacity planning)

Access budget status via TaskBudget methods.

Structs

TaskBudget

Tracks execution time budget for a task.

Enums

YieldReason

Reason Ring 1 yielded control.