nx2: notes 120-122 (cache lock contention, shader translation, final measurements)

1 files changed, 3 insertions, 0 deletions

diff --git a/NX2_NOTES.md b/NX2_NOTES.md
index 7171982b85..ad8a2f66dd 100644
--- a/NX2_NOTES.md
+++ b/NX2_NOTES.md
@@ -175,6 +175,9 @@ With the patched decoder, games 1/3/4 only leave ~60-110 rare SIMD encodings in
 | 117 | macro calls: ~1,000,000 a second, 7 instructions each, 96% exact repeats | the per-call interpreter cost was the time, not the instructions | memo of calls that depend only on their parameters and the data RAM words they read (1cd4a3c, b75fdf8, c28ea9a for compute macros): 97% replayed, verified on 200,000 recorded calls |
 | 118 | crashes ~26 s in (fencing thread walking a corrupt operation list; query cache Barriers; Vulkan worker SubmitExecution) | `async_presentation=true` (config): 4 crashes in 8 runs with it, 0 in 6 without; a race between the present thread and the Vulkan scheduler | keep it off (test build 3b). The fence manager's SyncOperation also appended to a list SignalFence moved from another thread: own lock now |
 | 119 | (tester, RTX 4070 SUPER) 50 MB log; textures evicted with 3 GB VRAM unused | nx2:vi2 104/105 called ~75 times a second through the logging auto stub; collector thresholds from Eden's ~7 GB device memory cap | quiet stubs (649fb56); thresholds from the driver budget (49225dd) |
+| 120 | GPU thread asleep ~8% on the texture/buffer cache mutexes | holders: the fencing thread (it took both caches for every fence, one per compute dispatch, and holds the buffer cache while it copies GPU-written buffers back) and CPU write traps; std::recursive_mutex slept at once | spinning recursive mutex, per-cache fence flush flags, separate locks (f10767f): asleep 3.7%. Buffer downloads at every fence stay: the native MME DMA reads of indirect arguments depend on them (no synchronous flush logged with them on) |
+| 121 | first-run freezes from shader translation (one 28,102-instruction compute shader: 3.4 s on the GPU thread) | BreadthFirstSearch's visited list was a linear scan (quadratic), and GlobalMemoryToStorageBufferPass searched again for every access | hash set past 64, per-start memo (ba173b6): 0.85 s; runtime builds now ~2-4 ms each. Translating on workers was not done: environments read live GPU state (texture types, constant buffer values) while translating |
+| 122 | final clean run (attract loop): 21-25 ms per frame in most 3D stretches, 26-38 ms in compute-heavy courses (industrial, highway), host GPU ~38% busy | the GPU thread is still the limit: draw setup ~25%, command parsing and register writes ~15%, compute dispatches/inline uploads (heavy courses) | open: per-draw binding cache, uniform buffer copies (staging slices are recycled by tick, so reuse needs care), buffer download interval sets |
 
 Run settings used (in `build/bin/user/config/sdl2-config.ini`): `memory_layout_mode=4`
 (12 GB). Debug knobs: `EDEN_NX2_TC_EXPECTED_MIB` / `EDEN_NX2_TC_CRITICAL_MIB` (collector thresholds),