prometeu-runtime/discussion/workflow/plans/PLN-0093-add-render-telemetry-counters-and-events.md

id	ticket	title	status	created	ref_decisions	tags
PLN-0093	vm-render-parallel-execution-boundary	Add Render Telemetry Counters and Events	done	2026-06-05	DEC-0031	runtime renderer telemetry diagnostics

Briefing

DEC-0031 requires render drops, repeats, stale discards, render errors, and present errors to be observable without becoming VM semantics.

Objective

Add the minimum render telemetry surface required for asynchronous render diagnostics and certification.

Dependencies

• Source decision: DEC-0031.
• PLN-0089 and PLN-0092 provide main event sources.

Scope

• Add minimum counters and last-frame IDs from DEC-0031.
• Add event recording hooks for handoff, consume, present, repeat, stale discard, errors, and shutdown discard.
• Expose telemetry through existing runtime/host diagnostics patterns.
• Ensure VM program behavior cannot observe telemetry as render ACK.

Non-Goals

• Do not build a UI profiler.
• Do not add VM syscalls for present ACK.
• Do not define host-specific logging formats beyond necessary hooks.

Execution Method

1. Locate current telemetry facilities and atomic counter patterns.
2. Add render telemetry structure with counters and last IDs.
3. Wire replacement-before-consume from handoff.
4. Wire consumed/presented/repeated from consumer path.
5. Wire stale epoch and shutdown discards.
6. Wire render/present error reporting.
7. Add read-only diagnostics access for host/debug tooling.

Acceptance Criteria

• All minimum counters and IDs from DEC-0031 exist.
• Latest-wins replacement is measurable.
• Repeated presents and stale epoch discards are measurable.
• Telemetry is not a blocking ACK path for the VM.

Tests

• Unit tests for counter increments.
• Handoff replacement telemetry test.
• Stale epoch discard telemetry test.
• Error path telemetry test where render/present errors can be simulated.

Affected Artifacts

• Runtime telemetry modules.
• RenderManager.
• Render handoff and publication paths.
• Host/debug telemetry readers.