iai VS dhat-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Is lai no longer maintained?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.

dhat for heap profiling

You could wrap the global allocator similar to dhat to instrument heap allocations. dhat itself depends on std.

I'm no expert in this, but I think you'll want something like https://github.com/nnethercote/dhat-rs

I am requesting comment on a new design for my dhat-rs profiling crate at https://github.com/nnethercote/dhat-rs/issues/17.

https://github.com/nnethercote/dhat-rs is a bit like this, albeit for heap allocation profiling. But it's experimental and I'm not really maintaining it right now.

https://github.com/nnethercote/dhat-rs is an incredibly useful tool, but to slow to run in production.