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Show HN: Hyperfine – a command-line benchmarking tool
- sharkdp 7y agoI have submitted "hyperfine" 1.5 years ago when it just came out. Since then, the program has gained functionality (statistical outlier detection, result export, parametrized benchmarks) and maturity. Old discussion: https://news.ycombinator.com/item?id=16193225 https://news.ycombinator.com/item?id=16193225 Looking forward to your feedback!
- dwohnitmok 7y agoSince you cite bench as an inspiration, have you ever thought about including the nice graphical HTML page with graphs that bench outputs? In a similar vein what are your thoughts on directly depending on and using criterion (the Rust port)?
- sharkdp 7y agoThank you for the feedback. No, we never thought about HTML output. However, there are multiple other export options and we also ship Python scripts that can be used to plot the benchmark results. The script is not very large, so far, but we are happy to add new scripts if the need for one should arise. What kind of diagrams would you like to see? Also, I have never thought about using criterion.rs. My feeling was that it is suited for benchmarks with thousands of iterations, while we typically only have tens of iterations in hyperfine (as we typically benchmark programs with execution times > 10 ms). Do you have anything specific criterion feature in mind that we could benefit from?
- dwohnitmok 7y agoAh those were earnest questions, not feature requests in disguise :), especially the second question. I haven't so far had any need for either of those things while using hyperfine (although admittedly I've only used hyperfine for about 3 small projects). I ask purely as a comparison to some of the design choices bench made for personal edification. That being said, one of the hypothetical advantages of using criterion is that you get to piggy-back on its visualizations and statistical analyses, which are quite useful for showing friends and coworkers. I'm not sure of the specifics of how you're doing outlier detection, but Criterion's method is quite nice and I find the choice of linear regression for linearly increasing iterations to be an interesting sanity check. Criterion can work for lower iterations as well (although tens is definitely getting into the lower bound).
- mplanchard 7y agoI started using hyperfine a few months ago now on a colleague’s recommendation and I really like it. In the past, I’ve cobbled together quick bash pipelines to run time in a loop, awk out timings, and compute averages, but it was always a pain. Hyperfine has a great interface and really useful reports. It actually reminds me quite a bit of Criterion, the benchmarking suite for Rust. I also use fd and bat extensively, so thanks for making such useful tools!
- sharkdp 7y agoThank you very much for your feedback!
- kqr 7y agoMost -- nearly all -- benchmarking tools like this work from a normality assumption, i.e. assume that results follow the normal distribution, or is close to it. Some do this on blind faith, others argue from the CLT that "with infinite samples, the mean is normally distributed, so surely it must be also with finite number of samples, at least a little?" In fact, performance numbers (latencies) often follow a heavy-tailed distribution. For these, you need a literal shitload of samples to get even a slightly normal mean. For these, the sample mean, the sample variance, the sample centiles -- they all severely underestimate the true values. What's worse is when these tools start to remove "outliers". With a heavy-tailed distribution, the majority of samples don't contribute very much at all to the expectation. The strongest signal is found in the extreme values. The strongest signal is found in the stuff that is thrown out. The junk that's left is the noise, the stuff that doesn't tell you very much about what you're dealing with. I stand firm in my belief that unless you can prove how CLT applies to your input distributions, you should not assume normality. And if you don't know what you are doing, stop reporting means. Stop reporting centiles. Report the maximum value. That's a really boring thing to hear, but it is nearly always statistically and analytically meaningful, so it is a good default.
- JoshTriplett 7y ago> Report the maximum value. In benchmarks, assuming you run the same workload each time, you often want the minimum value. Anything else just tells you how much system overhead you encountered. (Complete agreement that applying statistics without knowing anything about the distribution can mislead.)
- virgilp 7y agoTo be pedantic, you want the mode of the distribution. You are right though, the minimum is a much closer approximation of the mode in most situations.
- dzamlo 7y ago[This article](https://tratt.net/laurie/blog/entries/minimum_times_tend_to_mislead_when_benchmarking.html https://tratt.net/laurie/blog/entries/minimum_times_tend_to_...) explaib why using the minimum time may not be a so great idea.
- breck 7y agoThis is great! I was looking for something like this a year ago for benchmarking imputation scripts as part of a paper. This would have been awesome to use. Will keep it in my in the future.
- Myrmornis 7y agohyperfine is really nice! FWIW I wrote a rough first version of a tool that runs a hyperfine benchmark over all commits in a repo and plots the results in order to see which commits cause performance changes: https://github.com/dandavison/chronologer https://github.com/dandavison/chronologer