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Comment by burntsushi | Hacker News Reader

Consider using a bigger haystack. Your timings are so short that you're mostly just measuring the overhead of running a process.

This is relevant to krep because it spawns threads to search files (I guess for files over 1MB?).

This does not mean your benchmark is worthless. It just means you can't straight-forwardly generalize from it.

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The incorrect results are far more important than the times!

I agree.

That's a good point, though the readme does flatly state that krep "is designed with performance as a primary goal," so the lede's generalization that it is "blazingly fast" isn't correct, despite the later, more deeply buried caveat that "Performance may vary based on hardware, file characteristics, and search pattern" (which describes all software). And the comment you answered doesn't say just that krep is "slower" than fgrep; it says krep "produces obviously wrong results" slower.

Edit: and the fact that krep lacks regular-expression support means it's not a replacement for grep or meaningfully comparable with it.

I try my best to interpret pithy phrases describing a project as first order approximations, rather than literal statements of truth that perfectly generalize. Pithiness is important for communicating ideas quickly, but precision and pithiness are often in tension with one another. So I adjust my expectations accordingly.

Yes, I agree that the wrong results are bad. But that doesn't invalidate my point. I even went out of my way to clarify that the benchmark wasn't worthless. Benchmarking the small input case is absolutely worth it. You just can't tell much about its scaling properties when your measurement is basically "how fast does the process start and stop." Which, again, to be clear, IT MATTERS. It just probably doesn't matter as much as readers might think it matters when they see it.

So treat my comment as adding helpful context for readers that aren't experts in benchmarking grep tools from someone experienced in... benchmarking grep tools. :-) (And regexes in general. See: https://github.com/BurntSushi/rebar)

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