Upstream PR 2997 Vertex Remap Copy

Upstream PR #2997 — Speed up remapped vertex copies

Upstream work · Actionable research · Research and retired work

Current disposition — November 1, 2026

Reviewed: November 1, 2026. Fork source: b7140848 (full SHA b71408480a3a979a9c584663e1d1f400904c8bb7). Latest stable checked: v0.8.136-0-g458730bf5373, September 30, source 458730bf5373f1f0d027450fef7443e3af7a3ae1. GitHub state, branch recommendation, source presence and release availability are separate facts. See current status and release versus main.

Current field	November 1, 2026 observation
GitHub source	Upstream #2997
GitHub state / draft	Open / No
Current head	9e9773a53e318d75dcb7a8eecb2cb3f63c90a787
Originally reviewed head	9e9773a53e318d75dcb7a8eecb2cb3f63c90a787
Last metadata update (UTC)	2026-10-18T20:59:11Z
Head versus original review	Same recorded head; metadata/state updates do not indicate a new proposal-code head.
Current action	Contribute missing conversion/lifetime tests; avoid duplicate packing.
Fork/release availability	This upstream proposal’s GitHub state does not establish full fork/release inclusion. The historical overlap below is scoped to its recorded fork baseline; use the current feature register for delivered fork behavior.

The fork already contains pack_remapped_attributes(); do not propose importing that existing packing work again. Keep upstream’s sequence #2997 → #3002 → #3006 distinct: remapped copying does not establish demanded-format conversion or inline conversion, and vertex ownership remains independently important.

This refresh checked GitHub identity/state and the specific source boundaries named above. It did not rerun native games, XISO timings or integration qualification. Historical performance claims remain attached to their original heads.

Historical review — September 21, 2026

The review below is preserved as written, including its original state, head, fork baseline and proposed handoff. Its present-tense statements apply to that dated review; the current disposition above governs today’s action.

← Upstream Work

Field	Value
Upstream PR	xemu-project/xemu#2997
State at 2026-09-21 audit	Open
Reviewed upstream head	9e9773a53e318d75dcb7a8eecb2cb3f63c90a787
Last upstream update seen	2026-09-06
Reviewed upstream base	f9b14039e5bb56ae2d8f028e31e7cc19f13f7e12
Fork baseline	82d04d84bdb3de956f20c3537e1da2cece0e8da2
Relationship	Complementary to bounded vertex lifetime work
Related fork work	Mainkill1/xemu#85, Mainkill1/xemu#89
Contribution priority	Medium
Upstream contact status	No comment posted by this audit.

Summary

This is the first part of the documented vertex-remapping/conversion sequence before #3002 and #3006.

Upstream scope

The PR accelerates copies for remapped vertex data while preserving the guest source layout and constructing a host-consumable destination.

Corresponding fork work

The fork’s checked fetch spans and bounded versions define source-byte ownership and lifetime while remapping occurs.

Difference that must remain explicit

Lifetime protection does not implement format conversion or prove the remapped destination layout. Conversely, a fast copy must not weaken pending-draw ownership.

Transferable regression and review cases

• Preserve guest source stride, first-vertex offset, element width, and checked bounds.
• Remapped destination layout matches pipeline vertex descriptions.
• Pending draws retain prior source generations across rewrite/rollover.
• Measure bytes converted and fallback frequency, not only draw cadence.

Suggested upstream handoff

Offer source-span and lifetime tests as integration coverage. Preserve upstream’s sequence #2997 → #3002 → #3006.

Claims this page does not support

• It does not prove the upstream branch merges cleanly with current upstream.
• It does not prove a native correctness or performance result unless a linked exact-head run says so.
• It does not transfer favorable performance percentages between hardware, renderers, games, or source heads.
• It does not authorize posting a comment or review upstream.

Before sending anything upstream

• Refresh the PR state, head SHA, description, changed files, and newest review comments.
• Recheck the corresponding fork implementation on current main.
• Run or cite the narrow regression on an exact source state.
• Verify every public link and remove private paths, captures, game data, credentials, and internal logs.
• Phrase source concerns as source concerns and reproductions as reproductions.
• State the uncovered behavior and evidence limit.
• Add the posted URL and upstream response to this page.

Tracking log

Date	Upstream head	Action	Result
2026-09-21	9e9773a53e31	Fork/upstream source comparison recorded	Handoff prepared; nothing posted

References

• Upstream PR #2997
• Fork repository
• Upstream Work
• Pull Request Lessons