2 Commits

Include renames

Author	SHA1	Message	Date
dtourolle	3b5d564495	Try every GPU, not only the fastest one ... `request_adapter` with `HighPerformance` returns one adapter and no second chance. That is right on a healthy machine and wrong on one with a sick GPU, which is not rare: observed 2026-08-29 on a laptop whose discrete card had hit an NVRM assertion failure and a fullchip reset. The driver still advertised it, wgpu dutifully picked it as the highest performing, and the process died on it — while a working integrated GPU and a working external card sat unused in the same enumeration. A photo editor that will not start because the *fastest* GPU is broken, on a machine holding two that are not, is worse than a slow one. So: enumerate, order by preference, take the first that yields a device. The ordering reproduces what `HighPerformance` meant, so a healthy machine picks what it always picked and pays one enumeration for it. A CPU adapter sorts last rather than being excluded — software rendering is a poor experience and a working one. Which GPU to prefer is now a policy rather than an assumption, because the fastest is not obviously the right one. A 24 MP frame is ~96 MB of RGBA and every upload and export readback crosses PCIe on a discrete card, where an integrated GPU shares memory and crosses nothing — and does not empty a battery. Measured before choosing a default, on this machine's Iris Xe against its RX 5700 XT. The fused colour pass is within 1.5x, which is the shape shared memory suits. The neighbourhood stage is 5-8x slower, and that decides it: clarity at 1920x1200 costs 20 ms on the iGPU, over the budget on its own at the smallest size tested. So `Performance` stays the default and `Efficiency` is offered rather than chosen (`DARKROOM_GPU=integrated`). docs/frame-budget.md carries the table, and says what it does *not* show: the harness renders from a resident texture and never uploads or reads back, so the transfer cost an iGPU avoids appears in none of it. Import, export and the thumbnail sweeps may well go the other way. What this cannot fix: a GPU sick enough to accept `request_device` and segfault afterwards, which arrives as a driver crash rather than an error. It moves the boundary from "the preferred adapter is unusable" to "unusable and dishonest about it".	2026-08-29 12:43:10 +02:00
dtourolleandClaude Opus 5	13deaa2fbb	Assert the frame budget, and commit the numbers behind the FR-DSP-2 verdict ... FR-DSP-3 states a latency requirement and nothing checked it, which makes it a wish. This adds the check and the measurements it guards. `docs/frame-budget.md` is the bench's output with the reading of §2's decision rule attached. The short version: every point-operation chain at every viewport size, fit and at 1:1, is inside 16 ms at the 99th percentile — the widest is 4.5 ms of GPU at 4K — so FR-DSP-2 should be rewritten rather than implemented. The measurement did find a stage that misses the budget, and it is the one §2 predicted: clarity's 52-pixel separable kernel costs 34 ms at 4K. Tiles make that worse rather than better, since a tiled convolution reads a halo per tile; the fix `local_contrast` already names for itself is a base computed at reduced resolution. The test guards the fused path and says so, at length, rather than quietly excluding the expensive stage and letting the tag imply otherwise (§7). What it asserts is exactly the claim the recommendation rests on: one dispatch over a viewport-sized target, at a full chain, is comfortably inside a frame. Two things the numbers forced: - The two cases are one `#[test]`. As two they ran on a thread each, contended for the same device, and took the 1:1 case from 2.5 ms to 14.9 ms — a measurement of the harness that would have flickered either side of the budget forever. - The CPU half of the frame is judged only in an optimised build. Composition is real per-frame work on the UI thread and belongs in the budget, but the workspace builds its own crates at `opt-level = 0` in dev and `cargo test` is a dev build, so measuring it there measures rustc. The GPU half is asserted either way. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>	2026-08-27 19:00:45 +02:00