Greg Pomerantz
2f4768f354
Three root causes, all fixed and verified on the Pixel 9 Pro: 1. Present phase (backend + renderer): VSYNC_LOCKED_RENDER defers the render to the vsync wake; RENDER_AHEAD presents the previous frame at the start of render() (phase = wake + ~1.1 ms) and holds the new frame one slot. Crash fix: a held wgpu frame must be PRESENTED, never merely dropped, before the next acquire (AlreadyAcquired panic at launch otherwise); discard_pending_frame presents too. 2. Full-res prefetch churn (src/lib.rs): the 8-slot full cache cycled through a ~20-cell viewport forever (137 decodes/20 s) and each eviction free()'d a 50 MB Vec on the UI thread (20-52 ms CPU spikes, ~7/s = the residual SLOWEV NonMain jank). Fix: 60 s tombstone cooldown on evicted paths (idle prefetch skips, urgent tap bypasses) + off-thread reaper for the freed blobs (insert: 21 ms -> 4 us). 3. (earlier) Skia final flush + Mailbox present mode (vendor, M3). Instrumentation (all behind --features perf): OTHR/INVK/INVK_TAG/FLCK lines for cross-thread closure timing and push-site tagging. Warm measured swipe, 8580-file grid: cadence median 8.33 ms (exact 120 Hz), p99 15.5 ms, 5/552 gaps >16.7 ms (0.9%, max 28.3 ms, zero >33 ms); PRES phase median ~994 us, zero late frames. Docs updated (docs/BUGS/scroll-jank-120hz.md, full scorecard + line reference). Also: vendored i-slint-core + wgpu-hal (vkshim interposition patch), vkshim profiling tooling, backend made a non-optional dep, debuggable flag for simpleperf (REMOVE before shipping).
104 lines
3.2 KiB
Rust
104 lines
3.2 KiB
Rust
// Copyright © SixtyFPS GmbH <info@slint.dev>
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// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
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use core::{marker::PhantomData, ops::Range};
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use euclid::num::Zero;
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use super::ShapeBuffer;
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#[derive(Clone)]
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pub struct GlyphCluster<Length: Clone> {
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pub byte_range: Range<usize>,
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pub glyph_range: Range<usize>,
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pub width: Length,
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pub is_whitespace: bool,
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pub is_line_or_paragraph_separator: bool,
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}
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#[derive(Clone)]
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pub struct GlyphClusterIterator<'a, Length> {
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text: &'a str,
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shaped_text: &'a ShapeBuffer<Length>,
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current_run: usize,
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// absolute byte offset in the entire text
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byte_offset: usize,
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glyph_index: usize,
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marker: PhantomData<Length>,
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}
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impl<'a, Length> GlyphClusterIterator<'a, Length> {
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pub fn new(text: &'a str, shaped_text: &'a ShapeBuffer<Length>) -> Self {
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Self {
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text,
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shaped_text,
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current_run: 0,
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byte_offset: 0,
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glyph_index: 0,
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marker: Default::default(),
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}
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}
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}
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impl<Length: Copy + Clone + Zero + core::ops::AddAssign> Iterator
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for GlyphClusterIterator<'_, Length>
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{
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type Item = GlyphCluster<Length>;
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fn next(&mut self) -> Option<Self::Item> {
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if self.current_run >= self.shaped_text.text_runs.len() {
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return None;
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}
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let current_run =
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if self.byte_offset < self.shaped_text.text_runs[self.current_run].byte_range.end {
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&self.shaped_text.text_runs[self.current_run]
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} else {
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self.current_run += 1;
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self.shaped_text.text_runs.get(self.current_run)?
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};
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let mut cluster_width: Length = Length::zero();
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let cluster_start = self.glyph_index;
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let mut cluster_byte_offset;
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loop {
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let glyph = &self.shaped_text.glyphs[self.glyph_index];
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// ShapeBuffer::new folds the run's start into the cluster index
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// the shaper reports, so this offset is already absolute.
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cluster_byte_offset = glyph.text_byte_offset;
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if cluster_byte_offset != self.byte_offset {
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break;
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}
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cluster_width += glyph.advance;
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self.glyph_index += 1;
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if self.glyph_index >= current_run.glyph_range.end {
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cluster_byte_offset = current_run.byte_range.end;
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break;
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}
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}
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let byte_range = self.byte_offset..cluster_byte_offset;
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let (is_whitespace, is_line_or_paragraph_separator) = self.text[self.byte_offset..]
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.chars()
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.next()
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.map(|ch| {
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let is_line_or_paragraph_separator =
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ch == '\n' || ch == '\u{2028}' || ch == '\u{2029}';
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(ch.is_whitespace(), is_line_or_paragraph_separator)
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})
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.unwrap_or_default();
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self.byte_offset = cluster_byte_offset;
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Some(GlyphCluster {
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byte_range,
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glyph_range: Range { start: cluster_start, end: self.glyph_index },
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width: cluster_width,
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is_whitespace,
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is_line_or_paragraph_separator,
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})
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}
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}
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