cargo-flamegraph

A simple cargo plugin that generates a flamegraph for a given workload. It can be used to profile anything, not just Rust projects! No perl or pipes required <3

Uses perf on linux and dtrace otherwise.

Windows is getting dtrace support, so if you try this out please let us know how it goes :D

Installation

flamegraph not cargo-flamegraph! (cargo-flamegraph is an inactive crate as of March 2019)

cargo install flamegraph

This will make the cargo-flamegraph binary available in your cargo binary directory. On most systems this is usually something like ~/.cargo/bin.

Examples

# defaults to profiling cargo run, which will
# also profile the cargo compilation process
# unless you've previously issued `cargo build`
cargo flamegraph

# if you'd like to profile your release build:
cargo flamegraph --release

# if you'd like to profile a specific binary:
cargo flamegraph --bin=stress2

# if you want to pass arguments, as you would with cargo run:
cargo flamegraph -- my-command --my-arg my-value -m -f 

# if you'd like to profile an arbitrary executable:
cargo flamegraph --exec="/path/to/my/binary --some-arg 5"

Usage

USAGE:
    cargo flamegraph [FLAGS] [OPTIONS] -- [[ARGS_FOR_YOUR_BINARY]]

FLAGS:
    -h, --help       Prints help information
    -r, --release    Activate release mode
    -V, --version    Prints version information

OPTIONS:
    -b, --bin <bin>              Binary to run
    -e, --exec <exec>            Other command to run
    -f, --features <features>    Build features to enable
    -o, --output <output>        Output file, flamegraph.svg if not present

Enabling perf for use by unprivileged users

To enable perf without running as root, you may lower the perf_event_paranoid value in proc to an appropriate level for your environment. The most permissive value is -1 but may not be acceptable for your security needs etc...

echo -1 | sudo tee /proc/sys/kernel/perf_event_paranoid

Improving output when running with --release

Due to optimizations etc... sometimes the quality of the information presented in the flamegraph will suffer when profiling release builds. To counter this to some extent, you may set the following in your Cargo.toml file:

[profile.release]
debug = true