xtermjs/xterm.js

Search is too slow

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#5,176 opened on Oct 3, 2024

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 (34 comments) (4 reactions) (0 assignees)TypeScript (16,196 stars) (1,574 forks)batch import
area/addon/searcharea/performancehelp wantedtype/bug

Description

Currently the search addon limits itself to 1000 highlights by default. Contrast this to monaco's 20000 results before it gives up highlighting. When we increase our limit to 20000 the search itself ends up blocking the renderer pretty significantly.

Here is a profile using my i7-12700KF 3.61 GHz:

test file test.txt

Image

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Note that the search is also not incremental, so all successive searches take the same amount of time even for non-regex searches. https://github.com/xtermjs/xterm.js/issues/5177

VS Code issue: https://github.com/microsoft/vscode/issues/230365

Contributor guide

Tech stack
typescript
Domain
frontendperformance
Issue type
performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Familiarity with xterm.js search addonBasic profiling skills
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the search addon in xterm.js (likely in addons/search/). The issue shows that increasing the highlight limit causes renderer blocking; profile the search function to identify bottlenecks. Consider implementing incremental search to avoid re searching non regex queries (see linked issue #5177). Evaluate using a web worker to offload search computation. The test file provided can be used to reproduce the slowdown.