63 lines
2.2 KiB
Markdown
63 lines
2.2 KiB
Markdown
---
|
|
id: PLN-0089
|
|
ticket: vm-render-parallel-execution-boundary
|
|
title: Introduce Render Handoff Abstraction
|
|
status: done
|
|
created: 2026-06-05
|
|
ref_decisions: [DEC-0031]
|
|
tags: [runtime, renderer, handoff, latest-wins]
|
|
---
|
|
|
|
## Briefing
|
|
|
|
`DEC-0031` requires a single-slot latest-wins handoff where the producer never blocks on render ACK and replacement before consumption is observable.
|
|
|
|
## Objective
|
|
|
|
Introduce a render handoff abstraction that can be used synchronously today and by a worker later.
|
|
|
|
## Dependencies
|
|
|
|
- Source decision: `DEC-0031`.
|
|
- `PLN-0093` should define telemetry counters before final instrumentation is wired.
|
|
|
|
## Scope
|
|
|
|
- Add a small handoff type or trait around one pending owned `RenderSubmission`.
|
|
- Support publish, take latest, replace pending, and drain/discard operations.
|
|
- Report replacement/drop events to telemetry hooks.
|
|
- Integrate the abstraction into `RenderManager` without starting a worker.
|
|
|
|
## Non-Goals
|
|
|
|
- Do not spawn a thread.
|
|
- Do not implement frame pacing.
|
|
- Do not change Shell UI default rendering policy.
|
|
|
|
## Execution Method
|
|
|
|
1. Locate `RenderManager::latest_complete_submission` ownership and publication flow.
|
|
2. Introduce a handoff module with single pending slot semantics.
|
|
3. Move `RenderSubmission` into the slot on publication.
|
|
4. Make `take_latest` transfer ownership to the consumer.
|
|
5. Count replacement when a pending submission is overwritten before consumption.
|
|
6. Keep current synchronous publication working by immediately taking and rendering through the same abstraction.
|
|
|
|
## Acceptance Criteria
|
|
|
|
- `RenderManager` no longer relies on an unconstrained raw `Option<RenderSubmission>` for the future worker boundary.
|
|
- Publishing a newer pending submission replaces the old one without blocking.
|
|
- The consumer receives owned submissions.
|
|
- Replacement before consume is observable.
|
|
|
|
## Tests
|
|
|
|
- Unit tests for empty take, publish/take, publish/replace/take, and drain/discard.
|
|
- Integration smoke test that existing synchronous render still presents frames.
|
|
|
|
## Affected Artifacts
|
|
|
|
- `crates/console/prometeu-system/src/services/vm_runtime/render_manager.rs`
|
|
- New or existing render handoff module under `crates/console/prometeu-system`.
|
|
- Render manager tests.
|