# Explicit PlayerLoop timing verification — 2026-09-27 ## Candidate and contract - Unreleased Plan 13 candidate on `3f098937e9198a17edcf72cd75e73bd5bc76e2fd`; package version remains 0.3.14. Unity 2022.3.62f2, CLI 1.0.0-beta.11. - Added explicit Update, FixedUpdate and LateUpdate timing, immediately after their script callbacks. `Yield` targets the next occurrence; `NextFrame` and `DelayFrames` enforce rendered-frame distance. Existing overloads and the legacy runner remain unchanged. - A separate session owner installs before scene loading, repairs only its own nodes in the current loop and retires accepted waits on exit. Successful repair retains queues; failed repair faults/detaches them. No loop watchdog or ECS dependency was added. - Cancellation callbacks only set flags. Main-thread publication removes a source and disposes its registration before invoking consumers. Phase pass and session epoch checks protect reentrant registration and teardown. - [Usage and ownership](../../guide/onitytask.md#playerloop-timings). ## Editor verification | Run | Passed | Failed / skipped | | --- | ---: | ---: | | EditMode, default optimization | 780 / 780 | 0 / 0 | | PlayMode, default optimization | 64 / 64 | 0 / 0 | | EditMode, Release optimization | 780 / 780 | 0 / 0 | | PlayMode, Release optimization | 64 / 64 | 0 / 0 | | Windows Mono Release Player smoke | 22 / 22 | 0 / 0 | | Windows IL2CPP Release Player smoke | 22 / 22 | 0 / 0 | - Three new EditMode and ten grouped PlayMode cases cover validation order, phase placement and reentrancy, multiple actual fixed ticks in one rendered frame, paused worker cancellation, native/bridge/preserved consumption, current-loop repair, foreign nodes, failed repair, epochs, ECS coexistence, legacy-runner independence and two actual reload-disabled Play sessions. - The first lifecycle test passed its Awake and in-Play assertions, then incorrectly required its scene component to remain alive after ExitPlayMode. It now checks retained managed result fields after exit while keeping the live-component guard before exit. Runtime code did not change. - Initial PlayMode compilation found two unqualified `Time.frameCount` uses inside a SystemBase test. Qualifying UnityEngine.Time corrected the test's name binding. The next run passed 63/64; its remaining setup assumption exposed the preexisting legacy-runner teardown gap described below. - Final normal EditMode preceded the new PlayMode fixture and smoke staging; runtime and EditMode sources are identical. Final PlayMode and Release EditMode use the corrected fixtures. Benchmark-only dispatch additions were staged afterward for Player builds. ## Measurement boundary The separate `timing` suite brackets the actual injected Update node with cached Before/After nodes. Each work window schedules 128 tokenless native Yield operations, registers cached callbacks, runs the real cancellation scan and drain, consumes every result once and returns pooled sources. Readings end before validation/reporting. Three warmup cohorts precede eight samples of two cohorts: 384 warmup and 2,048 measured waits per process. Holder/delegate construction, loop installation, iterator/report work and counter calibration are outside the bracket. Empty and retained 64 KiB positive controls pass through the same bracket layout. Failed controls or invalid samples leave allocation unverified; raw readings remain in JSON. HeapDelta is coarse and process-wide: zero means no measured heap growth, not proof of zero GC allocation. No UniTask speed comparison is made. | Backend | Run | Mean ns/wait | HeapDelta bytes/wait | Valid allocation samples | | --- | ---: | ---: | ---: | ---: | | Mono | 1 | 621.73 | 0 | 8 / 8 | | Mono | 2 | 361.23 | 0 | 8 / 8 | | IL2CPP | 1 | 400.54 | 0 | 8 / 8 | | IL2CPP | 2 | 403.32 | 0 | 8 / 8 | All four processes passed both counter and same-bracket controls: 69,632 bytes for the 64 KiB allocation and zero for the empty control. Every raw work sample read zero. This supports no measured heap growth for this warmed, tokenless Update Yield path. Token registrations, cold installation, pool growth, other phases and other frame-wait variants are not covered by this allocation probe. Mono timing varied considerably; these times establish no general speed claim. Both Players use non-development Release, context flow enabled, internal context support and runner capacity 128 with tracking disabled. IL2CPP uses native Release and Minimal stripping. Build GUIDs are `d327acfd324741b9908580ac78d53860` (Mono) and `a0d4b9d503d74724a4358d8d4b277d55` (IL2CPP). All three saved settings hashes were restored and the temporary scene removed. No owned build/test ran during a measurement process. An unrelated Editor remained open; its sampled CPU increase was 0–0.03125 seconds over process windows of 0.48–0.99 seconds. Environment sidecars retain these observations; this is not an exclusive-machine timing experiment. ## Separate legacy limitation Destroying the legacy OnityTaskRunner can orphan its own pending waits. Its OnDestroy retires Jobs and the dispatcher but does not drain the three legacy wait lists; token callbacks cannot rescue those abandoned entries. The new injected wait completed successfully in the failing test. The final test completes its legacy setup wait before destruction to isolate independence. This existing limitation was corrected in the subsequent bounded [legacy retirement step](onitytask-legacy-retirement-2026-09-27.md), with saved source versions, callback reentrancy, replacement ownership and session closure checks. The measurements above retain the earlier source revision. It was not a regression introduced by explicit timing. ## Evidence - [Test results, including initial failures](onitytask-stage3d-playerloop-2026-09-27/test-results-summary.json). - [494 source/assembly/metadata hashes](onitytask-stage3d-playerloop-2026-09-27/source-hashes.json). - [Mono smoke](onitytask-stage3d-playerloop-2026-09-27/plan13-stage3d-mono-smoke.json), [IL2CPP smoke](onitytask-stage3d-playerloop-2026-09-27/plan13-stage3d-il2cpp-smoke.json). - Raw timing: [Mono 1](onitytask-stage3d-playerloop-2026-09-27/plan13-stage3d-mono-timing-run1.json), [Mono 2](onitytask-stage3d-playerloop-2026-09-27/plan13-stage3d-mono-timing-run2.json), [IL2CPP 1](onitytask-stage3d-playerloop-2026-09-27/plan13-stage3d-il2cpp-timing-run1.json), [IL2CPP 2](onitytask-stage3d-playerloop-2026-09-27/plan13-stage3d-il2cpp-timing-run2.json). - [Provenance, initial fixture identities and log hashes](onitytask-stage3d-playerloop-2026-09-27/provenance.json). No commit, push or release was performed. Full UniTask parity remains unfinished.