Upstream PR 3047 DSP Core DMA Overhaul

Upstream PR #3047 — DSP core and DMA performance/accuracy overhaul

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 #3047
GitHub state / draft	Open / Yes
Current head	5b1c1404c55a8748143ab37e4141b6779f656703
Originally reviewed head	5b1c1404c55a8748143ab37e4141b6779f656703
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	Open proposal; refresh integration and focused tests before handoff.
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 current head matches the recorded September review head. Later updated_at metadata does not establish changed proposal code. The original fork overlap remains a dated source comparison, not a fresh integration or native qualification result.

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#3047
State at 2026-09-21 audit	Open draft
Reviewed upstream head	5b1c1404c55a8748143ab37e4141b6779f656703
Last upstream update seen	2026-09-14
Reviewed upstream base	f9b14039e5bb56ae2d8f028e31e7cc19f13f7e12
Fork baseline	82d04d84bdb3de956f20c3537e1da2cece0e8da2
Relationship	Complementary snapshot lifecycle requirement
Related fork work	Mainkill1/xemu#53
Contribution priority	Medium
Upstream contact status	No comment posted by this audit.

Summary

The upstream DSP execution/DMA overhaul must preserve pause, quiesce, snapshot, restore, and resume ownership.

Upstream scope

The PR changes DSP core and DMA behavior for performance and accuracy.

Corresponding fork work

Fork #53 quiesces DSP execution before snapshot load and resumes through a controlled lifecycle. Its reproducer is more relevant than renderer FPS data.

Difference that must remain explicit

A faster/new DSP core does not automatically preserve snapshot worker and DMA ownership. Successful ordinary playback does not qualify paused/load transitions.

Transferable regression and review cases

• Snapshot while DSP work/DMA is active, then restore repeatedly.
• Pause → save → load while already paused.
• Quiesce acknowledgment precedes state replacement; resume occurs exactly once.
• Backend switch/shutdown leaves no worker touching replaced state.
• Compare audio and guest-visible DSP state after restore.

Suggested upstream handoff

Offer #53’s snapshot-load quiescence contract and reproducer as lifecycle qualification for the new core.

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	5b1c1404c55a	Fork/upstream source comparison recorded	Handoff prepared; nothing posted

References

• Upstream PR #3047
• Fork repository
• Upstream Work
• Pull Request Lessons