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Author SHA1 Message Date
iris 3c7d3db370 iris: the arenas upload deltas, and stop being 11x bigger than the tree
Changing any primitive re-uploaded every primitive. Measured over the
bench fixture by the new arena_churn rig: 758 MB across a fling and
1.2 GB across 401 streamed deltas, p50 3.0 MB per streamed frame.

Three separate things were wrong, and only the first is what it looked
like from the outside.

ArrBuf reallocated on every length change. A fresh Buffer's contents are
undefined, so adding one glyph -- which a streamed reply does constantly
-- forced a full rewrite, and no partial upload could have been correct
in the first place. It has a capacity now, growing geometrically and
never shrinking, and update() answers whether the Buffer identity moved
so a caller can rebuild its bind group and force the whole range dirty.
That alone took the glyph array from 95% re-uploaded to 3%, and stopped
primitive_group being rebuilt on every frame the arena changed.

A redraw freed its primitives and pushed new ones. Freed slots are not
reusable until the end of the frame -- a layer's draw order still names
them -- and Painter::draw_twice is how a container learns a child's
size, so with containers nested the arena's high-water was the transient
push count rather than the live one: 17 million pushes across 401
deltas, 127,443 slots for 11,569 live primitives, growing linearly with
the transcript. A redraw now gets its old handles back as a recycle pool
(Painter::take_recycled, Primitives::recycle) and writes into the slots
it already holds; the pool is consumed in order and whatever the draw
does not claim is freed when it ends. The arena is exactly the live
count now. The CPU frame improved with it, from p50 2.20ms to 1.39ms on
the stream run, because the freeing and the draw-order renumbering went
away.

Nothing tracked which entries changed. util::Dirty is a bitset per
uploaded array, coalesced into ranges at a 1 KiB gap. Marking is O(1)
and allocation-free; reading it back is one word per 64 entries. Both
alternatives were measured and rejected: a min..max span is nearly the
whole buffer, since a frame's changes land in 5-20 scattered runs, and a
Vec of indices would mean an allocation and a sort per frame at several
thousand marks. It replaces Primitives::updated -- one bool that covered
the instances and the per-primitive data together, so rewriting a rect's
region re-uploaded every glyph -- and TrackedArena::changed.

The trap only the rig could catch: writing an entry is not changing it.
Recycling rewrote every glyph of every moved row with identical bytes,
marking 73% of the glyph array against 0.6% genuinely changed, because
what moves is the instance's region and not the glyph. PrimitiveVec::set
and Primitives::set_instance compare before marking.

Every array now uploads within a hair of its floor: fling instances 3.4%
against 3.3%, fling glyphs 0.9% against 0.8%, stream glyphs 0.6% against
0.6%. Stream instances are at 72.7%, which *is* the floor and is a
layout question rather than an upload one -- the list is pinned to the
newest end, so a growing reply moves every row, and that should be one
move_offsets write rather than a redraw. Noted in RUST.md as the next
thing.

Also: draw_inner's four old_* parameters become one Retained struct, so
the recycle pool is a field rather than an eleventh positional argument
next to three others of the same shape; and free_primitive is the one
place a slot and its draw-order position are retired together.

The rigs move to scripts/rigs/ui-profile, a crate of their own so a
rig's dependencies stay out of the app's -- arena_churn needs bytemuck,
which nothing in ai-app does. arena_churn prints floor, uploaded and
whole side by side per array, because any two of those alone are
misleading and the 122x over-marking above was invisible until all three
were on screen together.
2026-09-09 02:14:51 -04:00
irisandClaude Opus 5 42d54eec95 Fling: the vsync clock, the frame ask, and a report that can say what it measured
Iris, from her phone: "some stuttering when flinging in particular.
Harder to notice with my finger directly moving the scroll." Her fling
phase was 103fps on a 120Hz screen at p50 6.3ms.

Two of the four things found are corrections to the instrument, not the
renderer. The swapchain acquire -- `get_current_texture`, which *blocks*
until the compositor frees an image -- was inside the span the report
called iris's CPU work, so a fling comfortably ahead of the display read
as milliseconds of being slow. A frame is now three measured parts
(`FrameParts`: build, acquire, submit), per phase as well as per run. And
nothing could say a frame was never *produced*: `late` counts frames that
cost too much, which a reader does not see, while a frame that never
happens leaves the last one up for two refreshes, which is the stutter.
`PhaseStats::missed` counts vsyncs nothing was drawn for. It closes on
the emulator: 1548 frames + 452 missed over 33.0s at 60Hz is 1980
vsyncs.

The other two are the frame loop. `Choreographer.postFrameCallback`
schedules for the next vsync after the call, and iris asked at the *end*
of the callback -- so any frame whose work ran past the boundary
registered too late and got the vsync after, one frame over budget
silently costing a second. It is asked for immediately after
`tick_animations` now, on both backends. And the fling was advanced on
`Instant::now()` rather than the vsync `do_frame` carries: frames are
presented on an even cadence whatever clock computes them, so sampling
the spline at "whenever the callback ran" moves the content unevenly with
no frame late enough to appear in any report -- and a drag never had it,
which is the asymmetry Iris described. `PointerClock` is `DeviceClock`
and the view keeps one, anchored by whichever of a touch or a frame comes
first, so a fling is advanced on the clock its velocity was measured on.

`opt-level` for the Android release build goes from "s" to 3. The table
in RUST.md picked "s" on bytes alone; over the same warm fling eight
times iris's own per-frame work is p90 0.15ms/p99 0.42ms at "s" against
p90 0.09ms/p99 0.26ms at 3, for 1.8 MB of arm64 APK.

`app-rust/tests/fling_profile.rs` is the rig that established what a
fling frame actually costs and is kept for next time (Iris: "please keep
the profiling rig around for future use"): only one frame in six lays
anything out, and the multi-millisecond spikes are all first-pass.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-09 00:49:28 -04:00
irisandClaude Opus 5 6d5a231f5c iris is the framework alone; the app is one crate in app-rust/
Iris: "the organization of the rust rewrite is a mess right now... there
shouldn't be anything related to the app inside of iris. Iris is supposed
to be the UI framework alone." And, on the crate count: "I'm confused why
the app only code needs more than one crate though."

Nine cargo workspaces become three, and the port's project code -- which
sat in five places, four of them inside the framework -- becomes one crate,
`ai-app`, in `app-rust/`:

  client-core                -> app-rust/src/client
  iris/transcript-ui         -> app-rust/src/ui
  iris/transcript-fixture    -> app-rust/src/ui/fixture.rs + tests/ + touch/
  iris/desktop-app           -> app-rust/src/desktop + src/bin_desktop.rs
  iris/android-app           -> app-rust/src/android + android-project/
  android-shell              -> app-rust/src/shell

iris/ keeps core, macro, the iris crate, tabs-ui and rig-input, and now
mentions no session, transcript, setup or server anywhere.

Only two of the old splits had a reason that survived reading. event-model
stays a crate at the repo root because server/ depends on it too, so a
crate is what makes the backend and the app agree by construction. The two
Android .so names looked like a hard constraint -- a package produces one
library artifact -- until P2 turned out to already plan merging those two
Android apps into one; both faces now come out of libai_app.so, picked
apart by features so `--no-default-features --features shell` keeps wgpu,
parley and iris out of the Compose app's APK. docs/RUST.md's "One app
crate" has the rest, including what each remaining feature is for.

DECISIONS.md and SUBAGENTS.md move into docs/ with everything else.

Verified: ./run-tests.sh and `cd iris && cargo test` green, clippy and fmt
clean in all five workspaces, `cargo ndk -t x86_64` links libai_app.so,
build-apk.sh produces an APK that installs and launches on this checkout's
emulator (Gl ... virgl, as expected), and the phone-sized headless
screenshot renders the transcript unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-08 23:36:38 -04:00