D250: getenv() caching fix -- root cause of the Dam fps drop (plus sysSleep unit fix, GE_D250 probe, perf.ps1) (#75)

* D250: fix sysSleep unit-conversion bug in frame-pacing; add GE_D250 lvlRender probe

port/fast3d/gfx_sdl2.cpp sync_framerate_with_timer() computed the
remaining frame budget in 100ns units (qpc_to_100ns) and passed it
straight into sysSleep(), which takes microseconds -- a real 10x
oversleep whenever that branch fires. Genuine bug, but only active
when target_fps is nonzero (tied to Input/Video FpsCap); confirmed via
live testing that it is NOT the active cause of the user's reported
~45-50fps with FpsCap=0/VSync=0, where this pacing path never runs.

Added GE_D250 (src/boss.c, #ifdef PORT) to isolate lvlRender()'s
DL-building cost (culling/animation/scene traversal) from gfx_run's
already-measured software-RSP interpretation cost. Live test on Dam
shows lvlRender averaging ~0.5-1.5ms -- also not the bottleneck.

Documented in docs/dev/GE-ENV-PROBES.md (GE_D250 row). findings.md
D250 update to follow after rebase.

Claude-Session: https://claude.ai/code/session_016DQUKGLZxFtPy52MkKXXog

* docs(D250): live A/B session -- MSAA/aniso/FOV/resolution/vsync all ruled out

Live session with the user driving the game directly, confirmed the
sim-healthy/render-sagging pattern from earlier idle testing reproduces
under real play on Dam. One-at-a-time A/B via the F10 overlay ruled out
MSAA, anisotropy, FOV, resolution (1280x960 fullscreen vs 640x480
windowed), and VSync (render never exceeds ~60 even uncapped) as the
cause -- the cost is resolution/GPU-setting-independent.

gfx_run (~6-10ms) + lvlRender (~0.5-1.5ms, via the new GE_D250 probe)
together don't account for the real ~20-22ms/frame. Leading remaining
suspect: the emulated N64 thread-handoff/scheduler round-trip
(gesched.c/sched.c) -- real OS context-switch/wake latency standing in
for what was free hardware handoff on N64. Needs a real profiler
(Visual Studio / WPR) attached during a live bad-fps moment to confirm;
ad-hoc per-call timers have now ruled out the two most obvious CPU call
sites without finding the cost.

Claude-Session: https://claude.ai/code/session_016DQUKGLZxFtPy52MkKXXog

* D250: fix uncached getenv() in fast3d hot paths -- root cause of the fps drop

A live WPR/xperf CPU trace (tools_pc/perf.ps1, new sister script to
debug.ps1) with Microsoft public symbols resolved found the dominant
render thread spending only 5.2% of its CPU time in the game's own
code -- 43% was in msvcrt.dll, and getenv()/_getenv_helper_nolock
alone accounted for ~50% of the thread's total CPU time.

Root cause: port/fast3d/gfx_pc.cpp's import_texture() (runs on every
texture bind) and several per-triangle/per-G_SETCOMBINE debug-probe
checks (GE_DTEX, GE_TEXDUMP, GE_TEXRAW, GE_D229 x2, GE_D172 x2, plus
GE_TEXDUMP/GE_PCDUMP in gfx_opengl.cpp) called getenv() uncached on
every call, unlike the safe static-cached pattern already used
elsewhere in this codebase. On a texture-heavy scene that's tens of
thousands of locked, locale-aware Windows CRT environment lookups per
second -- invisible to both of the timers added earlier this session
(gfx_run's own cost measurement and the new GE_D250 lvlRender probe),
since neither isolates CRT/library time from the game's own code.

Fix: cache every getenv() site in gfx_pc.cpp/gfx_opengl.cpp with the
established static-int pattern. Narrow, mechanical, no logic change.

Verified: the exact idle-Dam test that was pinned at 45-50fps before
the fix now holds a rock-steady 60-61fps, zero dips. Also explains why
the earlier MSAA/aniso/FOV/resolution/vsync A/B pass all showed "no
change" -- the getenv() cost was a large per-call constant that
swamped any real, smaller resolution-dependent GPU cost at every
setting tried.

Residual, separate issue found once this was fixed: still runs badly
at 1440p+ (640x480 now holds a clean 60fps) -- likely the real GPU
fill-rate cost the getenv() bug was masking, now exposed on its own.
Not yet investigated.

docs/dev/findings.md D250 updated with the full root-cause writeup.
docs/porting-notes.md gets a new lesson under section E (cache
getenv() in any hot-path probe). tools_pc/perf.ps1 automates the
trace-and-analyze workflow for next time.

Claude-Session: https://claude.ai/code/session_016DQUKGLZxFtPy52MkKXXog

* docs(D250): correct the 1440p+ follow-up -- it was a stale-build false alarm

User re-tested 1440p/4K on the actual getenv-fix build and confirmed
it holds up fine too. The "still runs badly at 1440p+" report was
from before the fix was live, same stale-build class as the DLL-load
false alarm earlier in the session. D250 is fully resolved across all
resolutions tested, not just 640x480.

Claude-Session: https://claude.ai/code/session_016DQUKGLZxFtPy52MkKXXog

* docs: add missing GE_D219RAW row to GE-ENV-PROBES.md (CI validate fix)

Pre-existing gap unrelated to this branch's own changes -- gen_env_probes.py
--check caught it now since it runs on every PR. GE_D219RAW has had live
getenv() sites in src/game/image.c since the D219 investigation but was
never added to the probe doc.

docs/dev/findings.md

@@ -527,7 +527,7 @@ covers D24–D69; the log continues in §H (D32 procedure, D70–D121).
 | D247 | **Black bars top and bottom of screen — possible aspect-ratio defect (M-116, user QA report).** Uninvestigated. Context: the port currently renders native 4:3 (640×480); widescreen is a *parked proposal* (`docs/dev/WIDESCREEN-FOV-PLAN.md` — PD-parity native 16:9 render, needs rule-#2 sign-off for its game-code HUD wave), so if the user's window/display is wider than 4:3 and the present path letterboxes to preserve aspect, the bars are current intended behaviour rather than a bug. If they appear in a 4:3 window too, it is a real defect (framebuffer sized wrong vs window, `videoCreateFramebuffer(w,h,upscale,autoresize)` → `gfx_create_framebuffer`). | **NOT A BUG — confirmed faithful, unmodified N64 decomp behaviour, no code change made.** `GE_PCDUMP` captures (both against the pre-existing save and a fresh-EEPROM run, to rule out a stale `Screen` option from earlier test sessions) show the exact same inset on Frigate: real scene content occupies rows ~20–459 of a 640×483 capture (the 483 vs 480 is a separate, harmless 3-row capture-tool rounding quirk, not investigated further), i.e. roughly 220/240 of the vertical field — and `src/game/fr.h:34` defines `VIEWPORT_HEIGHT_DEFAULT_NTSC 220` (240 for the full field), consumed unmodified by `bondviewGetCurrentPlayerViewportHeight()` (`bondview2.c:7858`) as the **default in-game viewport height whenever `PLAYER_OPTION_SCREEN` is `SCREEN_SIZE_FULLSCREEN`** (the decomp's own default value, `options.c:128`) — `VIEWPORT_HEIGHT_FULLSCREEN` (304, no inset) is a red herring name; it's only reachable via the `cameraBufferToggle` branch, not normal solo play. This is GoldenEye 007's well-documented original TV-safe-area letterboxing, baked into ground-truth decomp constants with no `#ifdef PORT` anywhere near it — the N64 game genuinely doesn't fill the full field during normal gameplay. Ruled out a stale/leftover EEPROM `Screen=Wide/Cinema` setting from earlier QoL-testing sessions as an alternative explanation: a fresh EEPROM (default options) shows the identical inset. **No fix needed; this row closes.** If the user's window shows noticeably *thicker* bars than this ~8–9%-per-edge margin, or bars appear on the *sides* instead of top/bottom, that would be a genuinely different (and real) symptom worth reopening under a new label — but "thin bars top and bottom, present at any window size" is correct, original behaviour. Cross-ref D226 (separate, already-tracked HUD-scale QoL ask — unrelated mechanism, don't conflate). |
 | D248 | **Port runs a stable 30 FPS instead of 60 FPS game-wide (M-117, user asked to verify FPS after the D209 timing-keystone fixes).** The port's pacemaker (`port/src/libultra.c` `portTickThread`) posts a VI-retrace event at a true 60Hz (NTSC) cadence, so the halving had to be somewhere downstream of that. | **FIXED, root-caused to a genuine pointer-width ABI bug in `src/sched.c` (compiled for the PC build, not excluded).** `osScAddClient()` (`src/sched.c:187-199`) stashes a per-client "present every retrace vs. every other retrace" flag by writing into the *next array slot's* `.next` field (`c[1].next = next`) rather than adding a real struct member — `gfxClient` (`src/init.c:246`) is registered with `next=NULL` (send every retrace → 60Hz) and the audio client `g_AudioClient[0]` (`src/audi.c:441`) with a nonzero sentinel `1` (send every other retrace → 30Hz, its intended cadence). `__scHandleRetrace` (`src/sched.c:334`) reads that flag back with a hardcoded byte offset, `*((s32*)client + 2)` (2×`sizeof(s32)` = 8 bytes). On the N64 (32-bit pointers) `sizeof(OSScClient)` is exactly 8 bytes, so offset 8 correctly lands on `client[1].next` — matching the write. On this 64-bit port `sizeof(OSScClient)` is 16 bytes, so the same hardcoded 8-byte offset instead reads the low 32 bits of `client->msgQ` itself (always a real, non-NULL pointer) — the gfx client's flag reads as permanently "nonzero" and silently falls onto the audio client's every-other-frame path, halving the game's real render/tick cadence to 30Hz although the retrace pacemaker itself was always ticking at the correct 60Hz. Same D122/D126/D132/D209 bug class (32→64-bit pointer-width struct-size growth desyncing a hand-rolled offset), just in the scheduler instead of a ROM-serialized struct. **Fix (`#ifdef PORT`, N64 line kept verbatim under `#else`):** read the real field by indexing the struct (`client[1].next == 0`) instead of hardcoding a byte offset — this naturally scales with pointer width on either platform and is the direct decompilation of what `osScAddClient`'s write side already does. **Verified:** `Video.DisplayFPS=1` overlay (`port/src/optionsoverlay.c`, D213) read a rock-stable "30 FPS" on `-level_09` (BUNKER1) pre-fix and "60 FPS" post-fix, same build/scene, screenshots captured via `GE_PCDUMP`. Rebuilt clean (`ninja -j1`, pre-existing unrelated warnings only); `-level_09` and `-level_20` both ran 12-30s post-fix with no crash (`ge007.crash.log` absent). No game-code files touched beyond this one mechanical read (`src/sched.c` is compiled for the PC target per `CMakeLists.txt`'s `SRC_ENGINE` list, not one of the excluded os/io files) and the audio client's own flag/path is completely untouched, so `#ifdef PORT`-gated audio pacing (D204 tempo work) is unaffected. **Note for `docs/dev/UNLOCKED-FPS-PLAN.md`:** this settles that plan's Phase 0 open question — the ~30fps default was a real port bug, not original N64 behavior or an artifact of retrace-rate tracking sim speed; the plan's default-preset baseline should be re-measured at the corrected 60fps before Phase 1 pacing work resumes. Not yet done: a full `verify.sh sweep` across all 21 levels (only `-level_09`/`-level_20` spot-checked this session) and a live human playtest for feel (input latency, animation smoothness, any level-specific perf regression now that render work happens twice as often per second). |
 | D249 | **LOD/culling breaks down on large open levels (Streets, Egyptian named specifically) at *default* FOV — far-away geometry has visible culling issues (M-119, user QA report).** Distinct from **D222** (which is specifically high `Video.FovScale` breaking *near-screen-edge* culling on NPCs/objects — not implicated here, default FOV) and from **D218** (the fog/far-clip *tint* boundary at wide FOV — also not the same symptom). This report is at the stock FOV, on the game's two biggest/most-open outdoor-scale levels, affecting *far* geometry specifically — points at either (a) a portal/room-visibility BFS cutting off too aggressively at range on large multi-room layouts (same neighbourhood as D233/D234's near-camera portal-cull bugs — worth checking whether D233's `gfx_sp_tri1` w<0 trivial-reject fix, which only guarded *behind-camera* vertices, has a sibling far-plane/depth-range case), or (b) GE's own N64 LOD/detail-swap system (mip-tile / simple-model substitution at distance — see D218's still-open question of "does GE have a separate geometry/object LOD-swap distinct from `Visibility.FarFog`") not being ported faithfully, popping or dropping geometry instead of swapping detail level. **Second, separate ask bundled in the same report:** the user would like LOD **improved** in general (presumably distance-based detail transitions look rougher/more abrupt on PC than remembered) but explicitly wants this **gated behind a toggle** so the original N64-accurate LOD behaviour stays selectable ("in case you want old school graphics") — i.e. this is a QoL feature request layered on top of a correctness bug, not one fix. | OPEN — not investigated. Next: reproduce on Streets (`-level_20`) and Egyptian (`-level_08`, confirm level id) at default `Video.FovScale`; `GE_PCDUMP` a long sightline where geometry visibly drops/pops, cross-referencing whatever governs GE's LOD-tile selection (`gfx_lod_tile_offset` family, already touched by D172/D219) and the portal/room-visibility walk (D233/D234 neighbourhood) to determine which of (a)/(b) is actually firing before designing a fix or the requested toggle. |
-| D250 | **FPS is inconsistent/low on many levels since the port started actually running at 60fps — drops to 20–40fps intermittently, described as worse than before (M-119, user QA report, follow-on from D248).** Very likely a direct consequence of **D248** shipping: the port's render+tick loop had been silently running at half rate (30Hz) for the entire life of the project (D248, M-118) — the *real* per-level CPU/GPU cost of rendering and simulating this port was always this high, it was simply invisible while D248 halved the work being asked of the hardware every second. D248's own write-up flagged this as an open risk ("any level-specific perf regression now that render work happens twice as often per second") and explicitly left a live playtest / perf pass as un-done. Not yet investigated which side (CPU sim, CPU fast3d command generation, or GPU draw) is the bottleneck, or whether it's uniform or level-specific (the user's report implies specific/intermittent, which fits a per-scene cost — draw-call count, overdraw, or a specific expensive subsystem — rather than a flat doubled baseline cost). **M-120: partial progress, real bottleneck not yet caught.** User report sharpened: ~45fps at 720p on a self-described high-end PC, present even outside of dedicated stress levels — worse than the coarse "many levels, intermittent" framing suggested. Two things ruled out this session: (1) **build flags are not the cause** — `build-pc/CMakeCache.txt` confirms `CMAKE_BUILD_TYPE=RelWithDebInfo` (`-O2 -DNDEBUG`) is the actual default (`CMakeLists.txt:75-76`, unconditional unless a cache already exists), matching what `./build-pc.sh` produces with no extra flags — a debug/`-O0` build is not the explanation. (2) **idle-load is not the bottleneck, at least not in this dev box:** `GE_D193=1` on `-level_09` (BUNKER1, small level) idles at a rock-steady `render=60 sim=60`, frame-render time ~2.5 µs·10^3 (2.5 ms); `-level_29` (STREETS, one of D249's flagged large/open levels) idles at `render=55-60 sim=60-62`, frame-render time 6-7 ms — both comfortably under the 16.7 ms/60fps budget with no catch-up clamp hits. **This does not reproduce the user's 45fps** — either the real cost only shows up under actual gameplay load (AI/combat/particles active, not an empty idle scene — matches D193's own "player fine, AI-driven cost is different" pattern) or it's resolution/GPU-fill-rate-bound in a way this box's small idle test window doesn't exercise (this session could not drive real keyboard/mouse input into the game to generate a loaded scene — no interactive input tooling available headlessly). Also spotted and ruled out in passing: the `D51 vi post` debug log firing every render frame in `port/src/libultra.c:781` is throttled to ~once/sec (`% 60 == 1`), not a per-frame cost — not the culprit, though it's a `TEMP D51` instrument that's been live since early porting and could be removed as cleanup. **Next (highest-value, needs the user's hands, not headless):** during a live play session where fps visibly tanks, run with `GE_D193=1` and capture a few seconds of its per-second `render=`/`sim=`/`clamped=` lines right at the slow moment — that alone tells us whether the *sim* side is what's slow (would show `sim<60`, meaning AI/physics is the cost) vs. the *render/GL* side (would show `sim=60` but `render<sim`, meaning fast3d command-gen or GL draw is the cost) or `-frame rendered in Nus` values from the same log spiking, without needing a real profiler build. Cross-reference **D249** (LOD/culling) once the bottleneck side is known — if it's render/GL-bound, over-drawn far geometry on large levels is a strong shared-cause candidate. |
+| D250 | **FPS is inconsistent/low on many levels since the port started actually running at 60fps — drops to 20–40fps intermittently, described as worse than before (M-119, user QA report, follow-on from D248).** Very likely a direct consequence of **D248** shipping: the port's render+tick loop had been silently running at half rate (30Hz) for the entire life of the project (D248, M-118) — the *real* per-level CPU/GPU cost of rendering and simulating this port was always this high, it was simply invisible while D248 halved the work being asked of the hardware every second. D248's own write-up flagged this as an open risk ("any level-specific perf regression now that render work happens twice as often per second") and explicitly left a live playtest / perf pass as un-done. Not yet investigated which side (CPU sim, CPU fast3d command generation, or GPU draw) is the bottleneck, or whether it's uniform or level-specific (the user's report implies specific/intermittent, which fits a per-scene cost — draw-call count, overdraw, or a specific expensive subsystem — rather than a flat doubled baseline cost). **M-120: partial progress, real bottleneck not yet caught.** User report sharpened: ~45fps at 720p on a self-described high-end PC, present even outside of dedicated stress levels — worse than the coarse "many levels, intermittent" framing suggested. Two things ruled out this session: (1) **build flags are not the cause** — `build-pc/CMakeCache.txt` confirms `CMAKE_BUILD_TYPE=RelWithDebInfo` (`-O2 -DNDEBUG`) is the actual default (`CMakeLists.txt:75-76`, unconditional unless a cache already exists), matching what `./build-pc.sh` produces with no extra flags — a debug/`-O0` build is not the explanation. (2) **idle-load is not the bottleneck, at least not in this dev box:** `GE_D193=1` on `-level_09` (BUNKER1, small level) idles at a rock-steady `render=60 sim=60`, frame-render time ~2.5 µs·10^3 (2.5 ms); `-level_29` (STREETS, one of D249's flagged large/open levels) idles at `render=55-60 sim=60-62`, frame-render time 6-7 ms — both comfortably under the 16.7 ms/60fps budget with no catch-up clamp hits. **This does not reproduce the user's 45fps** — either the real cost only shows up under actual gameplay load (AI/combat/particles active, not an empty idle scene — matches D193's own "player fine, AI-driven cost is different" pattern) or it's resolution/GPU-fill-rate-bound in a way this box's small idle test window doesn't exercise (this session could not drive real keyboard/mouse input into the game to generate a loaded scene — no interactive input tooling available headlessly). Also spotted and ruled out in passing: the `D51 vi post` debug log firing every render frame in `port/src/libultra.c:781` is throttled to ~once/sec (`% 60 == 1`), not a per-frame cost — not the culprit, though it's a `TEMP D51` instrument that's been live since early porting and could be removed as cleanup. **M-120 continued, live session with the user driving the game directly — the sim/render split is now confirmed live, and several strong candidates are ruled out, but the actual cost is still unlocated.** Reproduced directly on Dam (`-level_33`): `sim` holds a healthy 59-67/s throughout, `render` sags to 45-50/s, and the CPU-side `frame rendered in Nus` cost (`gfx_run`'s software-RSP interpretation, `port/src/libultra.c:1252`) stays only 6-10ms the whole time — comfortably under the 16.7ms/60fps budget. That leaves a genuine, unexplained ~10-15ms/frame, and a live A/B pass ruled out every obvious GPU-side suspect one at a time, each via the F10 in-game overlay while watching `GE_D193`: **MSAA 2→1 and Anisotropy 16→1 — no change.** **FovScale 125→100 — no change.** **VSync 1→0 (true uncapped rendering) — render still pinned at ~60 max, never higher, and the bad-scene numbers were unchanged** (also tells us the ~60fps ceiling itself is not a vsync artifact — something else already caps the loop at 60, vsync or not). **Resolution 1280×960 fullscreen → 640×480 windowed — no change** (rules out GPU fill-rate/pixel-count entirely; the cost does not scale with pixels at all). **Found and fixed a real, separate bug in passing (did not turn out to be the active cause here):** `sync_framerate_with_timer()` (`port/fast3d/gfx_sdl2.cpp`) computes the remaining frame budget in 100ns units (`qpc_to_100ns`) and passes it straight to `sysSleep()`, which takes **microseconds** — a genuine 10x oversleep whenever that branch fires. Fixed (`left / 10`). But this path only runs when `target_fps` is nonzero (tied to `Video.FpsCap`), and the user's test config had `FpsCap=0`/`VSync=0` — confirmed live that the bug fix made no difference to the reported drops, because the buggy code path was never executing in that config. Still worth landing as a correctness fix for whenever `FpsCap`/`VSync` *is* active. **Added `GE_D250`** (`src/boss.c`, wraps `lvlRender()`, the DL-building/culling/scene-traversal steLine truncated
 
 Phase 2 replaced the Phase-1 demo loop with the real `mainproc()` on real OS
 threads, compiled GE's real `src/sched.c`, and brought in PD's fast3d software