Add @ballocations macro for getting number of allocations

[nickrobinson251]

• matches to the @allocations macro recently added to Julia Base (Add @allocations macro for getting number of allocations JuliaLang/julia#47367)

[nickrobinson251]

bump :) is someone available to review this please?

[KristofferC]

I don't really understand the purpose of this macro and the @ballocated one. Why would you run a function potentially thousands of times (until the execution time is within some noise level) to count the number of allocations (which is not noisy). Isn't one for compiling the function and one for counting the allocations enough?

[nickrobinson251]

Isn't one for compiling the function and one for counting the allocations enough?

yeah, i think it probably is. And i intended to use it like @ballocations expression samples=2, and would be happy for this to default to samples=2 (is samples the right one? i guess evals=1 samples=2?)

the purpose is to have a standard, easy-to-use way to test the number of allocations (ignoring the compilation)

since @ballocated exists already, i thought @ballocations made sense (rather than defining such a macro in the tests of multiple packages)

but i think setting default evals/samples could make sense -- should i make that change?

[nickrobinson251]

i hope to use it the same way @ballocated is already used in e.g. the NamedDims tests: https://github.com/invenia/NamedDims.jl/search?q=ballocated

running these functions many times is no issue (since they're written to be basically no cost), but it's a lot nicer (i.e. less burden on the package developers writing the tests) to use @ballocated rather than having to makes sure things have already compiled and then using @allocated

[gdalle]

but i think setting default evals/samples could make sense -- should i make that change?

Sounds like a good idea to me, although it will have to be thoroughly documented for users not to be surprised.

[gdalle]

Can we set a default value evals=1 samples=2 for this one? And explain it in the docstring?

[gdalle]

Then again it would be incoherent with the other @bstuff macros so I'm torn