These are some files to determine performance of rustpython.

Running cargo bench from the root of the repository will start the benchmarks. Once done there will be a graphical report under target/criterion/report/index.html that you can use use to view the results.

cargo bench supports name matching to run a subset of the benchmarks. To run only the sorted microbenchmark, you can run:

cargo bench sorted

To view Python tracebacks during benchmarks, run RUST_BACKTRACE=1 cargo bench. You can also bench against a specific installed Python version by running:

PYTHON_SYS_EXECUTABLE=python3.13 cargo bench

The benchmarks are also run on every pull request by CodSpeed, which measures them with CPU simulation instead of wall time. criterion is aliased to codspeed-criterion-compat, so nothing changes for cargo bench: the compatibility layer only takes over when the CodSpeed runner drives the benchmarks.

To reproduce a CodSpeed run locally, install cargo-codspeed and the CodSpeed CLI, then run:

cargo codspeed build -p rustpython -p rustpython-sre_engine
codspeed run --mode simulation -- cargo codspeed run -p rustpython -p rustpython-sre_engine

Two things differ when the benchmarks run under CodSpeed:

• The CPython comparison benchmarks are skipped. They are useful to compare RustPython against CPython locally, but CodSpeed tracks the evolution of RustPython itself, and running them would double the duration of an already slow instrumented run.
• The microbenchmarks using ITERATIONS run with a single value of 1,000 instead of five sizes. CodSpeed retains the existing benchmark names; local runs include the iteration count in each benchmark id.

Simply adding a file to the benchmarks/ directory will add it to the set of files benchmarked. Each file is tested in two ways:

1. The time to parse the file to AST
2. The time it takes to execute the file

Parsing stops at an AST in both implementations. The CPython reference uses compile(..., flags=ast.PyCF_ONLY_AST) without compiling bytecode.

Execution includes compilation and runs each iteration with a fresh namespace whose __name__ is "__main__", so script entry points run in both RustPython and CPython.

Both Rust harnesses load only .py files and run workloads in filename order. Other entries, such as __pycache__ directories, are ignored.

Micro benchmarks are small snippets of code added under the microbenchmarks/ directory. A microbenchmark file has two sections:

1. Optional setup code
2. The code to be benchmarked

These two sections are delimited by # ---. For example:

a_list = [1,2,3]

# ---

len(a_list)

Only len(a_list) will be timed. Setup or benchmarked code can optionally reference a variable called ITERATIONS. If present then the benchmark runs at five sizes: 100, 300, 500, 700 and 900 iterations locally. For example:

obj = [i for i in range(ITERATIONS)]

ITERATIONS can appear in both the setup code and the benchmark code.

The optional pytest driver measures whole interpreter processes, including startup. Install pytest and pytest-benchmark, build RustPython with cargo build --release, and run from the repository root:

python -m pytest benches/test_benchmarks.py

It uses the release executable in target/release by default. Set RUSTPYTHON to the executable path when using a different build directory. Relative RUSTPYTHON paths are resolved from the directory where pytest is launched; absolute paths can be used from any directory. Script paths are resolved relative to this checkout, so pytest can also be launched from another directory. A failed subprocess fails the benchmark instead of producing a timing.

On MacOS you will need to add the following to a .cargo/config file:

[target.x86_64-apple-darwin]
rustflags = [
    "-C", "link-arg=-undefined",
    "-C", "link-arg=dynamic_lookup",
]

• https://benchmarksgame-team.pages.debian.net/benchmarksgame/program/nbody-python3-2.html
• The workloads marked as adapted from pyperformance come from python/pyperformance 1.14.0. Their pyperf runners and internal timers are removed so Criterion is the only measurement harness, and some input sizes are reduced for CodSpeed simulation.