Jason LukerandClaude Fable 5.1 2a61a05fd4 GPU: the readback deadline worker sleeps until a deadline is due instead of polling every 100 ms ...

`Readbacks::new` spawned a thread that slept 100 ms and checked for expired readbacks forever,
whether or not anything was pending: ten wakeups a second for the life of every desktop session
with a GPU compositor (12–13 idle wakeups/s measured, against 0.4–1.8 for the sibling apps).

The worker now waits on a condition: indefinitely while nothing is pending, otherwise until the
earliest deadline or until what is pending changes (start, complete, cancel, retire poke it).
It owns the state behind an `Arc<Inner>` rather than the `Readbacks`, so dropping the context
closes it instead of leaking the thread. Timeout, exactly-once callbacks, panic isolation and the
browser's timer path are unchanged.

Measured on an M2 Max (release build, window on screen, 60 s samples, A/B interleaved): idle
wakeups 12.15/s → 2.63/s not frontmost, 12.36/s → 2.72/s frontmost.

Tests: an idle worker does not wake; a due deadline wakes it when due; dropping the context stops
it; the existing panic/strand test moves deadlines through a hook that notifies the worker.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

2026-10-29 15:40:56 -07:00

..

src

GPU: the readback deadline worker sleeps until a deadline is due instead of polling every 100 ms

2026-10-29 15:40:56 -07:00

Cargo.toml

fix: contain GPU initialization and retire failed readbacks

2026-10-06 16:40:12 -05:00