set up benchmarks with asv

[d-v-b]

Sets up very basic benchmarks using asv.

I don't want to write up all of the benchmarks we need in this PR. this is just setting up the basic infrastructure.

[d-v-b]

closes #337

[d-v-b]

there might be better / alternative tools than asv for this purpose, like codspeed. I picked asv because that's what numpy is using, but the choice of tool is definitely a degree of freedom here.

[maxrjones]

there might be better / alternative tools than asv for this purpose, like codspeed. I picked asv because that's what numpy is using, but the choice of tool is definitely a degree of freedom here.

IMO it depends on your goals. If you want to run comparisons between two branches locally then asv can be fine. If you want the benchmarks integrated into CI then codspeed would work better. I personally prefer codspeed because I've found it easier to integrate with existing tests rather than needing separate a benchmarking setup.

[d-v-b]

generally I'm hearing more enthusiasm for something like codspeed instead of asv, and the argument in favor of benchmarks being integrated with our tests is persuasive to me, so I'm going to close this