Routine scheduler benchmark

Local macOS arm64 run, 2026-09-16, Zig 0.16.0 ReleaseFast. Reproduce from src/hikari with zig build routines-bench -Dgame-src=<absolute-game-src> -Doptimize=fast (one command). This is a synthetic headless workload; it excludes gameplay logic, rendering, physics, and editor lifecycle costs.

Each cohort reserves 64 KiB per fiber, warms all fibers, then measures 240 ticks. The ready workload increments a counter and calls nextTick; sleeping fibers wait 1,000 simulation seconds. The tick budget is 1,024 resumptions, not the entire cohort. Timings include scheduler and these minimal function bodies.

Stack budgets exclude metadata, guard pages, and platform rounding and are not measurements of resident RAM. The near-zero sleeping figures describe the empty ready-path check at this clock's measurement resolution. They do not include initial stack reservation, first-resume page faults, or waking all sleepers. A ready population of 100,000 takes about 98 ticks per service round at this budget. Changing the budget trades latency against frame CPU cost.

Cancelling and draining all 100,000 sleepers took 147.53 ms total across 98 passes; the ready cohort took 48.26 ms across 98 passes. These are total cleanup costs, not single-frame costs. Play Stop stages routine cleanup before retiring the owning game subsystem and actor storage. Reserve/admission and cancellation-marking costs are not preemptible; configure capacity during setup.

The harness fails on capacity/admission errors, lost cleanup, sleeping work executing early, exceeded resumption budgets, or failure to service the stable ready cohort within the measurement window. These numbers are one local run, not platform guarantees; Windows runtime performance has not been measured here.