[moretti]

Summary

Donkey Kong Bananza (040074A01BF12000, v458752) fell to 30 fps for seconds in busy scenes on the Mac, such as the second world's dialog close-ups (18,000-24,000 draws), although the Mac shows those frames at 50-60 fps.

The game's fixed-refresh frame-rate controller (main+0x204a18) measures each frame from its start to the later of its submission and its GPU end. On the Mac, the host's translation (about 15 ms) and the GPU (about 12 ms) come one after the other in that measure. That makes about 27 ms, over the controller's 20 ms limit, so after two late frames it moved to present interval 2.

 frame-rate controller (main+0x204a18)
   cost = max(submit, gpu end) - frame start
-  candidate = cost over budget ? interval + 1 : interval       (clamped 1..3)
+  candidate = settings' minimum (1)                             (main+0x204abc: csinc w9,w11,w9,ge -> mov w9,w8)
   up after 2 late frames, down after 6 under

• patches.py: the cut above. A late frame is shown when it is ready, instead of being held to 30 fps. The fixed-interval path (cutscenes at interval 3) is not touched.
• game.tsv: enc_thread on. Translation on the submit thread in the close-ups goes from 15.6 to 12.6 ms.
• The game's note and docs/agents/game-patches.md (regenerated) describe both.

This is complementary to #1389. That PR runs the game's own VRR controller on screens of 120 Hz and more. This cut covers the fixed-refresh controller, which every other screen uses, and #1389's controller when it drops below 40 fps.

Evidence

The host profiler (#1041), Mac M5 Pro, fullscreen, the same close-ups:

• Before: present interval 2 for seconds at a time, 30 fps.
• After: a 129 s session averaged 57.9 fps through the close-ups. That is 55-57 fps at about 23,000 draws, and 60 fps up to about 19,000.
• dm/tools/patch_nso.py on v458752's main changes exactly 4 bytes, at 0x204abc.
• test_docs.py and test_launcher_settings.py pass.

Open, in the game's note:

• whether the game's time keeps real time when frames run late;
• the last 1-2 ms of translation in the heaviest views.

Merge Danger

Door: two-way

The cut is gated to v458752's build ID, so other builds keep the game's controller unchanged.

Blast Radius: one-game

It affects Donkey Kong Bananza v458752 only, on the Mac and on iOS (the encode thread is already on for every game on iOS).