Migrate benchmarks to criterion?

[ysimonson]

This would pull in another dependency, but it's maybe worthwhile:

• The benchmarks could be run on stable
• It would generate better stats
• Results can be graphed
• It would be easier to compare branches

[lightsing]

Yes, I noticed this too. Current bench method cannot seperate "setup" and "bench" code.

I'm not sure how to migrate the macro part like full_bench_impl to criterion.

[ysimonson]

Yeah if the two can't be combined, that would be a show-stopper.

Maybe it's possible with a combination of OnceCell and bench_with_input, where the former holds a vec of closures that construct databases with different underlying datastores. But that's pretty nasty.