libpython: Add helper library for benchmarking

[wenzeslaus]

An experimental collection of simple functions to help benchmarking
and reduce code duplication between benchmarks.

The current design ideas are be minimalist, pragmatic with no API promisses.
The tools are meant for developers tracking the latest development version.

Co-authored-by: Aaron Saw Min Sern (thread/nprocs benchmarking function)

[wenzeslaus]

@aaronsms I would be interested in what you think (I can't put you on review directly).

[wenzeslaus]

This is addressing some of the needs from @aaronsms's GSoC 2021, but see also [GRASS-dev] measuring cpu time for each module and estimating modules scalability which was not taken into account at this point.

[aaronsms]

I think this is nice to add, I have tried using this for r.benchmark and r.univar. For the resolution_plot, do you think it's better to have the results be fitted into the same plot just like nprocs_plot, even if the resolutions points are slightly different, because users can always choose call resolutions_plot multiple times if they want separate graphs. Having them sharing a same graph allows us to see how it scales against bigger inputs, for example;

[HuidaeCho]

For the resolution_plot, do you think it's better to have the results be fitted into the same plot just like nprocs_plot

I think it would be more useful to plot them all in the same plot just like nprocs_plot.

[wenzeslaus]

For the resolution_plot, do you think it's better to have the results be fitted into the same plot just like nprocs_plot

I think it would be more useful to plot them all in the same plot just like nprocs_plot.

Agreed. Done.

[wenzeslaus]

This now has documentation and test. Additional benchmarking, outputs, plots are left for future PRs.

[wenzeslaus]

I'm not sure if the test will run in the CI, but I did two rounds of dealing with the dependencies, so hopefully it will. I can't confirm that now, due to addon installation failing which fails the tests in CI.

I merged this anyway so it is available for @aaronsms and anybody who will be testing his work.