kinogaki-parallel

What it is

Scoped parallel work over disjoint output slices, sized by cost.

Kernels lend borrowed data to workers, so work runs on scoped threads (std::thread::scope); a persistent pool would need unsafe to lend borrows (owner decision 2026-10-15: stay safe, revisit later). Starting a thread costs about 8 µs on Linux and macOS but 60–250 µs on Windows, so the worker count is chosen per call site from measured costs:

each call site (its source location) remembers the time one item took;
every parallel run measures how long workers took to start;
thread k starts at about k·c and works until the end T, so W threads finish work B when B = W·T − c·W²/2: T = B/W + c·W/2, smallest at W = √(2B/c).

The first run of a site uses the caller's minimum block size. The calling thread always works from the start; one helper starts the others, so the caller is not delayed by thread creation. Results never depend on the worker count: callers write disjoint slices.

Helpers come from one process-wide budget (set_budget) within the calling thread's share (with_share); an application sharing the machine with its own user interface keeps cores free that way (see budget).

Used by

Crate	Repository	As	What it is
`kinogaki-capture-diff`	Core and the app	normal	Compares two sets of UI reference captures (`tools/ui_captures.py compare BEFORE AFTER`).
`kinogaki-cook`	Core and the app	normal	Studio's core cooking engine, the same for every network kind (the owner's rule: the cooking DAG for nodes is core's).
`kinogaki-geometry-view`	Core and the app	normal	Geometry, curves and B-reps in the viewport, independent of any GPU API: the SDK's standard values as surface packets (over the SDK's display triangulation and shading normals, so Solid draws what Render renders), the one picker that answers rays and boxes ...
`kinogaki-project`	Core and the app	tests	Studio's project files: a document as a Prism document.
`kinogaki-script-exec`	lib-script	normal	lib-script's engine: a column (batch) interpreter in safe Rust.
`kinogaki-scripting`	Core and the app	tests	Scripts over the standard values: lib-script's engine behind the SDK's `ScriptEngine`, and what a script sees of each value.
`kinogaki-workflows`	Workflows	tests	Tests alone: `tests/workflows` drives what a person does across the plugins the app ships, through the real editor offscreen.

Modules

budget (private)One process-wide budget of helper threads, each thread's share of it, and a hook run as every helper starts.112 lines

cancel (private)Cooperative cancellation: CancelToken, which an owner raises and long work polls.81 lines

costs (private)Measured costs: per-thread start time and per-item time of each call site.105 lines

run (private)Running blocks on the caller and scoped helpers.214 lines

What it is

Depends on

Third-party

Used by

Modules

Public types and traits

At the crate root