perf(text): change a text view's state only when a parse changes it - #3
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A TextViewState parses a small text on the UI thread. Two parts of that path wrote the state without changing it, and under GPUI Fast each write counts as a change for every view that read the state: - The first parse ran in the constructor and notified. TextView makes its state as element state, inside the render of the view that holds it, so the notify stamped the state as changed while that view was drawn. - The synchronous parse is still sent to the background parser, so later appends extend its document. The task receiving the parser's acknowledgement updated the state just to find nothing to commit. It did the same for a result whose revision is stale. A text view built for the first time therefore changed twice, once while it was drawn and once a frame later. A list whose rows build text views, like a transcript scrolled to rows it had not shown, repainted its scroll layer for every new row until the layer was demoted. A state being made now parses without announcing it: there is no selection to reset and no reader to tell. The receiving task reads the state first and updates it only to commit a current result.
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Oct 1, 2026
gpui-fast moves to f71b3fe. It compiles scroll layers in on macOS and iOS (aislopware/gpui-fast#9), and it fixes the overflow in a list layer's shift when the view holding the list is copied from the last frame (#8). gpui-kit moves to 25b62b08, whose text view no longer changes its state when it is first built (aislopware/gpui-kit#3). Navigator scrolling goes from 0.343 to 0.221 ms a frame, with every frame composited. A finished conversation panned at rest goes from 0.479 to 0.4215 ms. Every other frame stays within noise. Two tests assert that both lists composite every frame and are never demoted. Co-Authored-By: Claude Code
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A
TextViewStatewrote itself twice without changing:TextViewcreates the state as element state inside its holder's render, so under GPUI Fast that notify marks the state as changed while the holder is drawn.So every text view built for the first time changed twice. A list whose rows build text views, such as a transcript scrolled onto rows it had not shown yet, repainted its scroll layer for every new row until the layer was demoted.
Now a state being made parses without announcing it, since there is no selection to reset and no reader to tell. The receiving task reads the state first and updates it only to commit a current result.
Measured in Slopty with layers compiled in: a finished 80-turn conversation panned at rest goes from 0.524 to 0.4325 ms a frame (median of 8 alternating rounds), and its layer composites 393 of 600 frames instead of 4.5. The test that sees this is on Slopty's side, because it shows only while scroll layers are on.
Written with Claude Code.