joeylib2/PERF.md

# JoeyLib cross-port performance (UBER benchmark)

Regenerated 2026-07-05 (PERF-AUDIT-PLAN.md Phase 8, #25b) from
same-day captures of all four ports. This supersedes the 2026-07-04
Phase 0 baseline; every phase of the audit fix plan (0-8) has landed,
so these are the numbers the library actually ships with.

**2026-07-06 update:** the IIgs sprite column is now COMPILED. Finding
#77 (the loader/segment-BSS + malloc-heap reservation that forced the
codegen arena into the app's own BSS) was fixed toolchain-side and
JOEY_IIGS_SPRITE_CODEGEN was re-enabled; the four IIgs sprite rows were
re-captured (bench-iigs.sh) and jumped 5-25x (SaveUnder 104->543,
Draw 48->907, RestoreUnder 110->568, SaveAndDraw 15->376 ops/sec),
bit-identical to the interpreter goldens (diff-uber-hashes 45/45). The
ST and DOS columns are unchanged from the 2026-07-05 capture.

Also 2026-07-06: the Amiga `jlpFillRect` partial-width path was moved
onto the blitter (BLTAFWM/BLTALWM hardware edge masks + masked minterm),
which lifted `jlFillRect 16x16` 567->1153, `80x80` 71->269 (both from
below-floor to well above it), and -- because they build on fillRect --
`jlDrawLine V` 144->269 and `jlDrawRect 100x100` 122->203, all
hash-identical (Amiga 45/45). The one remaining Amiga below-floor cell
is `jlFillCircle r=40` (74%); a whole-circle asm routine was tried and
did NOT help (per-span dispatch is not the cost -- the 8-way-symmetry
overlap fill dominates), so it stays on the C span walker for now.

**2026-07-06, NATIVE-PERF Phase 0:** four WORKLOAD rows were added (see
NATIVE-PERF-PLAN.md) and the goldens refrozen at **49 lines** after a
clean regression gate (45 match + exactly 4 extras per port) and full
4-port cross-identity. The new rows measure what games actually do, and
they expose the real problem the per-op rows hid: `jlSpriteDraw
unaligned` runs at **5% (ST) / 9% (Amiga)** of the IIgs floor -- a
15x/12x cliff vs the aligned row, because only x%8==0 draws are
compiled on the 68k ports (see the plan's code-truth table). The
`gameFrame composite` row is the bottom line: **ST 9 / Amiga 18 /
IIgs 10 / DOS 18 frames/sec** for a modest game frame. Bonus finding:
cross-identity of the sweep16 row validated the ST/Amiga shifted c2p
walkers as pixel-perfect at all 14 previously-untested x phases.
(Re-capture note: IIgs input/audio rows wobbled vs the prior MAME run
-- e.g. jlAudioFrameTick 50223 -> 27612 -- run-to-run MAME variance on
cheap ops; hashes are unaffected and those rows gate nothing.)

**2026-07-06, NATIVE-PERF Phase 1 (draw side) LANDED:** all-shift
compiled sprite DRAW on both 68k ports. Amiga emits pre-shifted JIT
variants for all 8 bit phases; the ST emits per-phase thunk + data
tables driven by a shared masked-movem walker (spriteWalk.s) for all
16 intra-group phases, with the dispatcher's ST shift contract changed
to x & 15. jlSpriteCompile is now plan-based: it measures every
(shift, op) variant, greedily fits them under the uint16 offset cap
(draws first, save/restore as atomic pairs), and degrades to the
byte-aligned phases when the arena is too small instead of losing the
sprite. RESULT -- the alignment cliff is CLOSED: `jlSpriteDraw
unaligned` ST 40 -> 500 ops/sec (12.5x), Amiga 75 -> 803 (10.7x);
sweep16 ST 2 -> 32 sweeps/sec (512 draws/sec), Amiga 5 -> 50 (800
draws/sec). Unaligned now performs like aligned on both ports (ST 82% /
Amiga 84% of their aligned rows), and every one of the 49 golden
hashes still matches -- the compiled paths are bit-identical to the
interpreted walkers they replace, on all four ports. (Found along the
way: the Amiga bench task stack was ~4 KB -- one deep call chain from
overflow -- now 32 KB in bench-amiga.sh; the emitters' accumulators are
file statics.)

**Phase 1 step 5 (save/restore) ALSO LANDED, completing Phase 1:**
compiled save/restore on both 68k ports operate on the 16-px-group
window (two width classes per sprite, like the IIgs MVN pair), the
backup format is a pure function of the recorded geometry (identical
for compiled and interpreted producers/consumers -- the ST HAL gained a
raw-span interpreted branch, switched atomically with restore), and the
gates route by SPRITE_SAVE_CLASS / SPRITE_RESTORE_CLASS with an odd-
buffer-pointer demotion (68000 word ops need even addresses). The
combined jlSpriteSaveAndDraw path now fires on 68k at EVERY x for the
first time. RESULTS (floor-relative): Amiga SaveUnder 104% -> 276%,
RestoreUnder 98% -> 236%, SaveAndDraw 94% -> 160%; ST SaveUnder
158% -> 203%, RestoreUnder 122% -> 163%, SaveAndDraw 87% -> 107%;
Amiga gameFrame 18 -> 23 fps. Backup capacity contract:
JOEY_SPRITE_BACKUP_BYTES in sprite.h (window worst case; all in-repo
examples migrated + 2-aligned). DEFAULT_CODEGEN_BYTES is 64 KB on
Amiga/ST (full variant sets). All 49 golden hashes held throughout.

**2026-07-07, THE ST COLUMN DOUBLED -- idle-audio ISR tax found and
fixed:** every previous ST capture ran with ~49.5% of the CPU silently
consumed by the 12.3 kHz Timer-A PWM ISR that jlpAudioInit started
unconditionally -- it streamed buffer silence to the YM even with
nothing playing, and UBER inits audio before its timed run. Found by
a calibrated probe (known-cycle dbra spin + per-layer direct-call rows
under the bench Hatari config): every probe row slowed by exactly
1.98x once audio was initialized, and the probe's un-taxed tilePaste
cycles/call matched the instruction-count model that UBER's number
mysteriously doubled. Fix: src/atarist/audio.c Timer A is now
demand-driven -- installed on the first PlayMod/PlaySfx, parked again
once the mix buffer drains back to silence with nothing live
(drain-to-silence handshake in jlpAudioFrameTick; StopMod parks
immediately when no SFX is riding the pump). Probe-verified: idle rows
match the never-initialized rows exactly, the tax correctly returns
while an SFX drains, and it vanishes after the drain. Full ST
re-bench: 49/49 hashes bit-identical (pixels untouched) and EVERY row
~2x: gameFrame 9 -> 19 fps, tilePaste 1,574 -> 3,203/s, sprite draw
607 -> 1,188/s, unaligned draw 508 -> 992/s. The other three ports
were audited for the same bug class and are clean: Amiga ~1.8% idle
tax (PTPlayer rides Paula DMA), DOS ~0.5% (SB auto-init DMA, ~11 Hz
half-buffer IRQ), IIgs 0% (no handler installed until PlayMod). ALL
pre-2026-07-07 ST comparisons -- including the Phase-0 ceiling gaps
and the Phase-1 relative results -- understated the ST by ~2x.

**2026-07-07, NATIVE-PERF PHASE 2 COMPLETE -- Steps D3 (R6 + R10)
close the phase:** (R6) the IIgs masked-copy inner's 4 x 8 jsr/rts
round-trips to tmaskByte were inlined via the TMASK_BYTE assembler
macro (identical body; the row loop-back became brl -- the expanded
body exceeds 8-bit branch range): jlTileCopyMasked 625 -> 681 (+9%,
exactly the 384-cycle model). (R10) the stage arm of jlDrawPixel is
one fused JSL (iigsDrawPixelMark: single-row widen + nibble RMW plot
against the pinned stage base): jlDrawPixel 3,179 -> 5,576 (+75%, 502
cyc/call incl. wrapper vs the measured 880 before); the batching
plotters (lines/circles, plotPixelNoMark) keep the unfused inner and
were flat, as were tiles/sprites. Final gate 49/49 x4 + make
iigs-verify. PHASE-2 EXIT vs its gate ("small-op rows move measurably
toward Phase-0 ceilings on all ports; goldens hold"): tilemap row
tiles/sec ST 1,600 -> 4,050 / Amiga 2,300 -> 3,750 / IIgs 1,750 ->
2,950 / DOS 10,000 -> 12,900; gameFrame ST 9 -> 21 / Amiga 18 -> 25 /
IIgs 10 / DOS 18 -> 19; IIgs tilePaste ceiling gap 3.5x -> 2.15x, ST
2.6x. The remaining per-call floor is the public wrapper + one
JSL/call -- Phase 3 batching territory. Optional leftovers R7
(saveAndDraw consolidation) and R12 (IIgs C-residue reshapes) are
recorded in the plan, not phase-gating.

**2026-07-07, NATIVE-PERF Phase 2 Step D2 LANDED -- sprite dispatch
flattening (R5):** the spriteCompiled* runtime dispatchers moved from
spriteCompile.c into spriteDispatch.h as always-inline functions
consumed only by sprite.c, deleting the cross-TU call per compiled
sprite op and letting the compiler share the slot/field loads the
caller already did. Gated 49/49 x4. Sprite rows: IIgs +6-13%
(SaveAndDraw 376 -> 423, Draw 906 -> 966), ST SaveUnder +15% (2,611),
Amiga +5-11% (SaveUnder 2,053), DOS SaveUnder +16% (10,743). Two
measurement footnotes: gameFrame wobbles +/-1 fps between runs
(single-digit iters per 16-frame window -- quantization, not signal;
ST has bounced 21/22 across three consecutive gates), and DOS
`jlSpriteDraw unaligned` is BIMODAL across runs of identical binaries
(~3,800 vs ~5,100; seen 07-06 and again today; the all-phase sweep16
row is stable at ~362, so per-phase behavior is fine -- likely DOSBox
dynamic-core state; do not chase single-run deltas on that row).

**2026-07-07, NATIVE-PERF Phase 2 Step D1 LANDED -- IIgs fused tile
entries (R2):** jlTileFill/Copy/Paste on the stage now run ONE JSL
each: new joeyDraw.s entries (iigsTile*Mark, section
.text.iigsFusedTile) derive the destination in asm from the pinned
$01:2000 stage base + gRowOffsetLut, write via long,X with the stage
literal folded into each store, and widen the dirty band via a shared
stageTileMark helper -- replacing C-side pointer math plus two JSLs
(op + marker). Gated 49/49 (pixels) AND make iigs-verify (framebuffer
-- the mark half is hash-blind, so the display check is load-bearing).
RESULTS: IIgs tileFill 1,981 -> 3,251 (+64%), tilePaste 1,687 -> 2,710
(+61%), tileCopy 1,441 -> 1,988 (+38%), map row 35 -> 59 (+69% = 2,950
tiles/s), gameFrame 10 -> 11 fps; unfused controls (copyMasked, snap,
sprites) flat. IIgs tilePaste is now ~1,030 cyc/call vs the 480-cyc
hand-coded ceiling (gap 2.15x, was 3.5x). Toolchain landmine found en
route: a 16-bit jsr between .section blocks can cross OMF segment
banks (no link error, wild jump into $00CFxx) -- helpers must share
their callers' section or be jsl/rtl; see the cross-section-jsr
feedback memory.

**2026-07-07, NATIVE-PERF Phase 2 Steps A-E LANDED (per-op tax):**
five hash-gated steps, each 49/49 x4. (A) plane-pointer access
inlined into the 68k compiled-sprite dispatchers (amigaPlanar.h /
stPlanar.h; the jlpSurfacePlanePtr cross-TU call -- ~190 cyc x4 per
Amiga dispatch -- deleted): Amiga sprite ops +10-23%. (B) whole-tile
dirty marks specialized (band = [bx*2, bx*2+1] with compile-time
proof, unrolled 8-row widen): tiles +9-28% on 68k/DOS. (C) jlDrawRect
raw-edge fills + ONE band-identical mark (+22-40%); the multi-row
widen unroll is Amiga-only by measurement (gcc-mint compiled it WORSE,
ST -5% -- see the per-port #if in surface.c). (D=R9) presents consume
the core gStageScbDirty/gStagePaletteDirty flags instead of
memcmp'ing 512-712-byte cached mirrors: gameFrame +1-2 fps on
ST/Amiga/DOS. (E) ST/Amiga tile ops moved into always-inline per-port
headers (stTile.h / amigaTile.h), deleting the second cdecl layer
(ST tiles +9-14%, Amiga +5-11%), then the Amiga row loops unrolled to
d16(An) form (tilePaste +36%, tileSnap +52%). NET SESSION MOVEMENT on
the tile gate row (tiles/sec, map 10x5): ST 1,600 -> 4,000; Amiga
2,300 -> 3,750; DOS 10,000 -> 12,900. gameFrame: ST 9 -> 21, Amiga
23 -> 25, DOS 18 -> 19 fps (IIgs untouched at 10 -- its fused-asm
glue is Phase 2 Step D, still open). The present-row jumps (ST 467,
DOS 1,137) are the dirty-union idle early-out running flag-gated;
gameFrame is the honest present signal.

Correctness statement backing this table: all four ports produce
BYTE-IDENTICAL pixels on every measured op and every correctness
check -- **49/49** surface hashes match the frozen goldens in
tests/goldens/uber/ (37 timed ops + 12 hashed checks; the PASS/FAIL
checks -- palette round-trip, PRNG golden sequence, sprite clip
round-trip, arena churn, sprite-from-surface -- pass everywhere).
The Phase 0-era divergences (#75 tilePasteMono three-way, #78 ST
fillCircle/tileFill, #87 IIgs circle outline) are all fixed.

## Measurement honesty (read before trusting any number)

Four measurement artifacts have shaped this table's history. Three are
fixed, one is inherent -- know them before comparing rows:

1. **Per-iteration poll tax -- FIXED (Phase 0).** The pre-audit bench
   loop called jlFrameCount() between every op; on the IIgs that was a
   GetTick toolbox chain (~600-800 cycles), so every small-op number
   carried the harness cost, not the op cost. Ops now run in adaptive
   batches per poll. Small-op numbers jumped 2-10x on every port when
   this landed; never compare against pre-Phase-0 captures.
2. **SEI tick loss -- INHERENT on IIgs, rows tagged below.** The
   benchmark clock is jlFrameCount = the VBL-interrupt-driven GetTick.
   An op that holds SEI while it runs suppresses those interrupts, the
   clock loses ticks, and the op over-reports. The three SEI-holding
   rows -- `jlSurfaceClear`, `jlFillRect 320x200`, and
   `jlStagePresent full` -- are CLOCK-UNRELIABLE in the IIgs column.
   The physics check: a full-screen op moves 32000 bytes at ~6
   cyc/word, so ~29 ops/sec is the hard ceiling at 2.8 MHz. The
   present row's 68 and the clear row's 35 sit above it -- inflated;
   the honest values are at or below the ceiling.
3. **ST frame-rate miscalibration -- FOUND and FIXED 2026-07-06; the
   ST column below is the corrected (millis-clock) capture.** Before the
   fix, ops/sec was `iters * jlFrameHz() / actualFrames` and the ST's
   `jlpFrameHz()` hardcoded 50 -- but Hatari runs the emulated ST at
   ~60 Hz VBL, so every ST number was scaled by 50/60 ~= 0.83 (~17%
   pessimistic). Caught by cross-checking against UBER's independent
   Timer-C 200 Hz millis clock (refresh-independent), which ran ~16-22%
   faster; the Amiga's two clocks agreed exactly (FS-UAE = PAL 50 Hz),
   confirming it was ST-only. Two fixes landed: (a) UBER now computes
   ops/sec from `jlMillisElapsed` (refresh-independent on all four
   ports; identical to the old formula on IIgs where millis is
   GetTick-derived), and (b) ST `jlpFrameHz()` now reads the shifter
   resolution + sync-mode registers to return the true 50/60/71 Hz. The
   per-op `UBER-CLK:` log line reports frame-vs-millis as a standing
   cross-check (they now agree). ST cells rose ~17% (e.g. jlSpriteDraw
   503->585, jlFillRect 80x80 97->115); DOS/IIgs/Amiga unchanged.
4. **ST idle-audio ISR tax -- FOUND and FIXED 2026-07-07; the ST
   column below is the post-fix capture.** jlpAudioInit started the
   12.3 kHz Timer-A PWM ISR at init and left it running forever, even
   silent (~320 cycles/tick = ~49.5% of the CPU), and UBER inits audio
   before timing anything. Every ST capture before 2026-07-07 is ~2x
   pessimistic. Timer A is demand-driven now (runs only while a mod or
   SFX is audible), so the benches measure the op and an idle game
   gets the whole CPU. Amiga/DOS/IIgs audited clean for the same bug
   class (~1.8% / ~0.5% / 0% idle cost).

## Baseline (2026-07-07): absolute ops/sec per port

The IIgs is the reference and the perf floor (every other port must
meet or beat it -- project directive). Non-IIgs cells show absolute
ops/sec plus percentage of the IIgs number; sub-100% cells are bolded
as below-floor. `tools/uber-perf-table` emits this table directly;
regenerate after any re-capture (Amiga needs TIMEOUT=600 -- the
default cuts off the final checks). Capture provenance: ST 2026-07-07
(post-audio-fix); IIgs/Amiga/DOS 2026-07-06 (recovery-gate rerun,
unaffected by the ST fix).

| Op | IIgs (ops/sec) | Amiga (ops/sec, % of IIGS) | Atari ST (ops/sec, % of IIGS) | DOS (ops/sec, % of IIGS) |
| --- | --- | --- | --- | --- |
| jlSurfaceClear | 33 | 75 (227%) | 88 (267%) | 66 (200%) |
| jlPaletteSet | 1561 | 11403 (730%) | 10388 (665%) | 29809 (1910%) |
| jlScbSetRange | 163 | 3953 (2425%) | 4833 (2965%) | 8495 (5212%) |
| jlDrawPixel | 5576 | 5853 (105%) | 6522 (117%) | 23687 (425%) |
| jlDrawLine H | 1142 | 1753 (154%) | 2670 (234%) | 5708 (500%) |
| jlDrawLine V | 99 | 303 (306%) | 261 (264%) | 468 (473%) |
| jlDrawLine diag | 42 | **40 (95%)** | 88 (210%) | 109 (260%) |
| jlDrawRect 100x100 | 73 | 285 (390%) | 279 (382%) | 454 (622%) |
| jlDrawCircle r=16 | 304 | **285 (94%)** | 366 (120%) | 447 (147%) |
| jlDrawCircle r=80 | 70 | **63 (90%)** | 83 (119%) | 98 (140%) |
| jlFillRect 16x16 | 602 | 1153 (192%) | 1203 (200%) | 3013 (500%) |
| jlFillRect 80x80 | 110 | 285 (259%) | 240 (218%) | 414 (376%) |
| jlFillRect 320x200 | 21 | 68 (324%) | 77 (367%) | 58 (276%) |
| jlFillCircle r=40 | 42 | **31 (74%)** | 155 (369%) | 156 (371%) |
| jlSamplePixel | 4797 | 7253 (151%) | 9603 (200%) | 46397 (967%) |
| jlTileFill | 3251 | 3753 (115%) | 3855 (119%) | 11840 (364%) |
| jlTileCopy | 1988 | 2903 (146%) | 3445 (173%) | 10913 (549%) |
| jlTileCopyMasked | 681 | 1003 (147%) | 1632 (240%) | 3391 (498%) |
| jlTilePaste | 2710 | 3803 (140%) | 4033 (149%) | 12545 (463%) |
| jlTileSnap | 2530 | 6003 (237%) | 6403 (253%) | 19247 (761%) |
| jlSpriteSaveUnder | 602 | 2103 (349%) | 2611 (434%) | 10743 (1785%) |
| jlSpriteDraw | 966 | 1103 (114%) | 1283 (133%) | 6390 (661%) |
| jlSpriteRestoreUnder | 545 | 1453 (267%) | 1781 (327%) | 6246 (1146%) |
| jlSpriteSaveAndDraw | 423 | 753 (178%) | 892 (211%) | 4656 (1101%) |
| jlStagePresent full | 67 | 540 (806%) | 467 (697%) | 1132 (1690%) |
| jlInputPoll | 228 | 4003 (1756%) | 2841 (1246%) | 3148 (1381%) |
| jlKeyDown | 10191 | 39753 (390%) | 44448 (436%) | 77738 (763%) |
| jlKeyPressed | 11389 | 38003 (334%) | 44448 (390%) | 74907 (658%) |
| jlMouseX | 20214 | 97703 (483%) | 117920 (583%) | 155685 (770%) |
| joeyJoyConnected | 10191 | 38903 (382%) | 44260 (434%) | 77748 (763%) |
| jlAudioFrameTick | 27509 | 57003 (207%) | 39885 (145%) | 59372 (216%) |
| jlAudioIsPlayingMod | 11071 | 56403 (509%) | 60441 (546%) | 128214 (1158%) |
| surfaceMarkDirtyRect (via jlFillRect 32x32) | 323 | 853 (264%) | 788 (244%) | 1476 (457%) |
| jlSpriteDraw unaligned | 906 | **903 (100%)** | 1070 (118%) | 3837 (424%) |
| jlSpriteDraw sweep16 | 60 | **56 (93%)** | 68 (113%) | 362 (603%) |
| jlTilePaste map 10x5 | 59 | 78 (132%) | 80 (136%) | 259 (439%) |
| gameFrame composite | 10 | 25 (250%) | 21 (210%) | 19 (190%) |

> **IIgs full-screen ceiling (~29 ops/sec).** A full-screen op moves
> 32000 bytes = 16000 word-stores x 6 cyc (STA long,X / PEI, both
> 3 cyc/byte) / 2.8 MHz ~= 34 ms ~= 29 ops/sec maximum. So
> `jlSurfaceClear`, `jlFillRect 320x200`, and `jlStagePresent full`
> cannot legitimately exceed ~29; a higher reading means the benchmark
> clock was perturbed. The clock is `jlFrameCount` = the VBL-interrupt-
> driven GetTick, so an op that holds `SEI` while it runs can over-
> report its ops/sec. Treat full-screen IIgs numbers above ~29 as
> inflated and cross-check against the cycle model.

## Reading notes

* **Sprite rows measure COMPILED code on all four ports** since
  NATIVE-PERF Phase 1 (2026-07-06): the 68k ports JIT all-shift draw
  variants plus group-window save/restore (previously stubs that fell
  to interpreters), IIgs codegen re-enabled via finding #77, DOS via
  finding #74. The interpreted walkers remain only as arena-full
  degrade paths -- and are proven bit-identical to the compiled code
  by the 49-hash gate.
* **The below-floor cells are the standing punch list**, and after the
  2026-07-07 audio-tax fix the ST has NONE -- every remaining
  below-floor graphics cell is the Amiga's: the circle family (diag
  line 95%, circle r=16 94%, r=80 87%, fillCircle 74% -- planar 4-plane
  RMW tax) and the two sprite workload rows a hair under floor
  (unaligned 95%, sweep16 89%; chip-RAM display-DMA contention that the
  fast-RAM-code ST does not pay). DOS jlAudioFrameTick (42%) is the SB
  half-buffer silence refill on an otherwise-trivial call -- it gates
  nothing. Floor parity is effectively DONE; the open work is
  ceiling-relative (NATIVE-PERF-PLAN.md Phase 2+), where every port
  still runs 2-5x below hand-coded technique on tile/sprite glue.
  Amiga jlFillCircle r=40 (74%) was probed
  2026-07-06 with a full whole-circle asm routine (Bresenham + inline
  4-plane long-fill span): it held 45/45 hashes but did NOT move the
  number (34 vs 31, within the coarse 11-iter sample), so the per-span
  C dispatch is NOT the bottleneck -- the asm was reverted. The real cost
  is the midpoint fill's 8-way symmetry filling each row 2-4x (idempotent
  overlap): the true lever is a scanline rewrite (one span per row, no
  overlap), which would roughly halve the byte writes and stay
  hash-identical. NB: this op is timed at batch=1 (~29 ms each) by the
  50 Hz frame counter, a coarse measurement. (The old note here blaming
  a "4-5x model-vs-measured gap" partly on measurement was vindicated
  2026-07-07: on the ST that gap was the idle-audio tax, artifact #4.)
* **jlRandom has no timed row.** Phase 8 (#43) rewrote its xorshift32
  update in 16-bit halves on the IIgs only (~2-3x fewer cycles per
  call on the 65816; 32-bit shifts there are per-bit helper loops).
  Output is bit-identical -- host-proven over the golden sequence and
  a 50M-state sweep, and gated by UBER's random-golden check on all
  four ports.
* **Input predicates stay functions** (Phase 8 #40 decision): the
  post-clock-fix numbers (12K-77K ops/sec) put call overhead nowhere
  near a real frame budget; macro forms in the public header were
  rejected as not worth the API exposure.
* **IIgs libc memset/memcpy remain ~4x slow** (finding #79,
  toolchain-owned): llvm-mos runtime byte loops vs ORCA's MVN. The
  jlScbSetRange and jlPaletteSet IIgs rows carry that tax; library-side
  mitigations landed (#16 unrolled word copy, #21), the libc fix is
  flagged to the llvm816 session.

## History

Pre-2026-07-04 tables (ORCA-era IIgs column, artifact-inflated DOS
numbers, un-batched loops) live in git history only -- every
conclusion drawn from them was re-derived from Phase 0 onward. The
Phase 0 baseline (2026-07-04) and per-phase deltas are recorded in
PERF-AUDIT-PLAN.md's progress tracker; headline gains since Phase 0:
IIgs interpreted spriteDraw 18 -> 48 ops/sec (Phase 4), IIgs
tilePasteMono asm 3.35x (Phase 7 #3), ST flood plane hooks 5.6x
(Phase 7 #4), DOS paletteSet +92% / tileSnap +42% (Phases 2/5),
DOS compiled sprites 284 -> ~6100 ops/sec (#74).