My global config.toml setup for ultra fast Rust compile times

config.toml

[unstable]
codegen-backend = true

[profile.dev]
# Compile using cranelift for massively faster compilation
codegen-backend = "cranelift"
# If you want to attach a debugger, set this to true
debug = "line-tables-only"

# Consider compiling deps with cranelift if you want cold-compilation to be faster
[profile.dev.package."*"]
codegen-backend = "llvm"

# cranelift is `panic = abort`, so you need to compile with llvm to get `#[should_panic]` working
[profile.test.package."*"]
codegen-backend = "llvm"

# Disable cranelift for release profile
[profile.release]
codegen-backend = "llvm"

# cranelift cannot build wasm32-unknown-unknown out of the box
[profile.web]
codegen-backend = "llvm"

[build]
# Using a global target dir allows all projects to share incremental compilation results,
# vastly speeding up cold-compilation of new projects.
target-dir = "/home/hhh/.cargo/global-target"

[target.x86_64-unknown-linux-gnu]
rustflags = [
    # Compile faster
    "-Zshare-generics=y",
    "-Zthreads=8",
]
rustdocflags = [
    # Compile faster
    "-Zshare-generics=y",
    "-Zthreads=8",
]

[target.wasm32-unknown-unknown]
rustflags = [
    # Improve performance
    "--cfg",
    "web_sys_unstable_apis",
    "-Ctarget-feature=+sign-ext,+nontrapping-fptoint",
    # Compile faster
    "-Zshare-generics=y",
    "-Zthreads=8",
]
rustdocflags = [
    # Compile faster
    "-Zshare-generics=y",
    "-Zthreads=8",
]

Put the above in ~/.cargo/config.toml.
Requires:

• Linux
• nightly: rustup default nightly
• cranelift: rustup component add rustc-codegen-cranelift-preview --toolchain nightly
• Bevy CLI: cargo install --git https://github.com/TheBevyFlock/bevy_cli --locked bevy_cli

and assumes you run your apps with bevy run and bevy run web -U multi-threading