perf(desktop): coalesce streaming text/reasoning deltas per animation frame (#3114)#3501
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… frame The agent stream pushes a text/reasoning delta per Webview event; at 200 tok/s that is one state update every ~5ms, while rAF is 16ms — so the reducer was running 3-4 times per visible frame and the React tree was re-rendering the entire Message list each time. Add lib/rafBatch.ts: a tiny rAF-coalescing queue with a synchronous drain() so non-text events (tool_dispatch, usage, notice, turn_started/ done, message) flush any pending deltas first to keep causal ordering intact. Drain is also called on unmount so a turn-end that races the teardown doesn't strand the last few tokens in the buffer. tsc --noEmit passes; Go build ./desktop/... is clean.
… frame The agent stream pushes a text/reasoning delta per Webview event; at 200 tok/s that is one state update every ~5ms, while rAF is 16ms — so the reducer was running 3-4 times per visible frame and the React tree was re-rendering the entire Message list each time. Add lib/rafBatch.ts: a tiny rAF-coalescing queue with a synchronous drain() so non-text events (tool_dispatch, usage, notice, turn_started/ done, message) flush any pending deltas first to keep causal ordering intact. Drain is also called on unmount so a turn-end that races the teardown doesn't strand the last few tokens in the buffer. tsc --noEmit passes; Go build ./desktop/... is clean.
# Conflicts: # desktop/frontend/src/lib/useController.ts
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Lands the rAF streaming coalescer from #3114 (by @HUQIANTAO) on top of the current
main-v2.The original PR was written against the old single global
dispatch;main-v2has since moved the controller to per-tab dispatch (dispatchTo(targetTabId, …)). Re-applied the batching onto the new model:tabIdand flushes viadispatchTo, so coalesced deltas route to the correct tab;drain()first to preserve causal ordering (unchanged intent);onReady/syncActiveTabFromBackendsetup.Also trimmed
rafBatch.ts's comments to repo style (2-line header, 1-line whys) — logic unchanged.Original author attribution preserved.
Closes #3114