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# Objective Many of our benchmarks use [`criterion::black_box()`](https://docs.rs/criterion/latest/criterion/fn.black_box.html), which is used to prevent the compiler from optimizing away computation that we're trying to time. This can be slow, though, because `criterion::black_box()` forces a point read each time it is called through [`ptr::road_volatile()`](https://doc.rust-lang.org/stable/std/ptr/fn.read_volatile.html). In Rust 1.66, the standard library introduced [`core::hint::black_box()`](https://doc.rust-lang.org/nightly/std/hint/fn.black_box.html) (and `std::hint::black_box()`). This is an intended replacement for `criterion`'s version that uses compiler intrinsics instead of volatile pointer reads, and thus has no runtime overhead. This increases benchmark accuracy, which is always nice 👍 Note that benchmarks may _appear_ to improve in performance after this change, but that's just because we are eliminating the pointer read overhead. ## Solution - Deny `criterion::black_box` in `clippy.toml`. - Fix all imports. ## Testing - `cargo clippy -p benches --benches` |
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| src | ||
| Cargo.toml | ||
| README.md | ||
Bevy Benchmarks
This is a crate with a collection of benchmarks for Bevy.
Running benchmarks
Benchmarks can be run through Cargo:
# Run all benchmarks. (This will take a while!)
cargo bench -p benches
# Just compile the benchmarks, do not run them.
cargo bench -p benches --no-run
# Run the benchmarks for a specific crate. (See `Cargo.toml` for a complete list of crates
# tracked.)
cargo bench -p benches --bench ecs
# Filter which benchmarks are run based on the name. This will only run benchmarks whose name
# contains "name_fragment".
cargo bench -p benches -- name_fragment
# List all available benchmarks.
cargo bench -p benches -- --list
# Save a baseline to be compared against later.
cargo bench -p benches --save-baseline before
# Compare the current benchmarks against a baseline to find performance gains and regressions.
cargo bench -p benches --baseline before
Criterion
Bevy's benchmarks use Criterion. If you want to learn more about using Criterion for comparing performance against a baseline or generating detailed reports, you can read the Criterion.rs documentation.