emilk/egui

Improve compile times of `eframe`

Open

#4,481 opened on May 11, 2024

View on GitHub
 (4 comments) (6 reactions) (0 assignees)Rust (29,051 stars) (2,037 forks)batch import
dependenciesgood first issuehelp wanted

Description

eframe currently compiles in about 10s on my M3 MacBook Pro, as measured by

cargo clean && cargo build --timings -p eframe

Getting rid of proc-macros

A lot of that time is waiting for proc-macro and syn so that we can start compiling bytemuck, thiserror, and foreign-types-macros (used by core-graphics, which is used by winit).

Getting rid of the proc-macros in bytemuck should be simple (replace by manual implementation of its unsafe traits for Color32, Vertex etc). Likewise, replacing thiserror should also be fairly trivial.

I haven't looked into foreign-types, but even removing some proc-macro usage should allow some crates to start compiling earlier, hopefully reducing the total end-to-end compilation time.

Other stuff

  • ahash has a build.rs takes a full second to run
  • icrate takes 5-6 seconds of CPU time

wgpu

Switching glow for wgpu adds another 10s, i.e. doubling the compilation time. To investigate the compilation time of wgpu, run:

cargo clean && cargo build --timings -p wgpu

Contributor guide

Tech stack
rust
Domain
performancedeveloper experiencebuild system
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.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Rustproc macroscargo build system
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
First, run 'cargo clean && cargo build timings p eframe' to identify current bottlenecks. Then, focus on removing proc macro dependencies: manually implement bytemuck traits for Color32 and Vertex, and replace thiserror with manual error implementations. Investigate foreign types macros usage in core graphics to see if proc macros can be avoided. For wgpu, separately compile it with 'cargo clean && cargo build timings p wgpu' to analyze its compile time.