iai VS criterion.rs

The three popular options for benchmarking in Rust are: libtest bench, Criterion, and Iai.

Iai^1 uses CacheGrind^2 to count instructions

[1] - https://github.com/bheisler/iai

But, /u/bencherdev, please consider integrating iai measurements! By the same person behind criterion but designed for one-shot measurements that are stable in CI measurements.

Is lai no longer maintained? It hasn't had any commits in a year and a half.

Lately I've found that using unwrap_unchecked has nearly zero performance gain but all the UB to gain if you change the code one day. My source is iai which provides exact instruction counts and is entirely deterministic for any given execution (and almost-deterministic across different compilations of the same program).

Have you tried criterion.rs or iai ? The first is great at micro benchmarks and, if it is not enough, the second can catch even smaller performance difference.

In the mean time maybe https://github.com/bheisler/iai could be of help

Well, the most interesting one is probably Iai; an experimental benchmark framework that runs all of the benchmarks in Cachegrind for much higher precision and repeatability than is possible with Criterion.rs. It's still a work-in-progress, so I haven't published it on Crates.io yet. See the readme for a more detailed discussion of the pros/cons relative to Criterion.rs.

The three popular options for benchmarking in Rust are: libtest bench, Criterion, and Iai.

Holy crap. I was just writing a blog to complain about the state of Rust benchmarking and I think this might address most of my points. The biggest one is the ability to have benchmarks collocated within the library like tests which is the biggest annoyance.

It’s also nice to see that it can report multiple counters in parallel. I put up a similar feature[1] for criterion recently but I fear the project isn’t being maintained anymore…

Haven’t looked deeply into divan yet but the other requirements I have for criterion’s power is to run tests with statistical guarantees on the results, terminate quickly when statistical significance is reached (—quick), provide a comparison of the delta from a previous benchmark, and to run async code. Wonder how this stacks up.

[1] https://github.com/bheisler/criterion.rs/pull/722

criterion for benchmarks,

For an extra optimization, you might look into techniques like branchless code, turning array of structs into struct of arrays for better cache utilization/lowering branch mispredictions. There is many talks on YouTube how to actually measure and improve performance of native code. And for rust there is a criterion.rs for benchmarking.

https://github.com/bheisler/criterion.rs is good for tests like that. It will give you much more than a single number and handle things like outliers. This makes identifying noisy tests simpler.

I have tried many ways but I think is not possible. I put it on https://github.com/bheisler/criterion.rs/issues/631.

Criterion is still the gold standard.

Pros for Criterion over the stdlib: https://github.com/bheisler/criterion.rs#features

Downsides of Criterion: https://bheisler.github.io/criterion.rs/book/user_guide/know...