iai VS flamegraph

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Is lai no longer maintained?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.

You can install cargo-flamegraph with cargo install flamegraph. There are some underlying requirements to be able to use cargo-flamegraph; you will want to take a look at the repo here to make sure you have the right dependencies.

I tried to diagnose the issue with flamegraph, but unfortunately the flamegraph didn't show anything beyond the next call for some reason

having some tools to identify slowness origins (flamegraph is one... but not sure it's the way to go)

I'm currently implementing a solution for the first part of the day 16. It work but it is really slow... I'd like to : - understand why - having some tools to identify slowness origins (flamegraph is one... but not sure it's the way to go) - eventually have some clue/solution/idea - have general feedback on what in my "coding style" is not appropriate for rust (I come from java/kotlin/ts even if I've already coded a bit in c/c++) : for example I love iterator & sequence but i feel they are not really suited to overuse in rust (mostly because of async & result).

Use a profiler. Flamegraph is a good way to visualise profiler output. This lets you identify which functions are taking up a large amount of time - and hence helps you identify where to focus your optimisation efforts.

You tried trying to see what takes the most time under load via flames? https://github.com/flamegraph-rs/flamegraph

Well, in cases like that the answer is straight forward, use a profiler like https://github.com/flamegraph-rs/flamegraph

I don't see any obvious problems with your algorithm. I've had luck using cargo-flamegraph to identify the slow parts of my code. That's going to show you which parts to focus on improving the performance of!

From the readme of cargo flamegraph: