Support for async functions

[quambene]

I was trying out divan, and I'm wondering if there is support for benchmarking async functions, e.g. using a tokio runtime (cf. https://bheisler.github.io/criterion.rs/book/user_guide/benchmarking_async.html#benchmarking-async-functions)?

Feel free to close this issue if this was answered elsewhere.

[nvzqz]

I plan to support async functions and have some code in progress for it. This will likely come soon after allocation profiling. It wouldn't be until after or during the end of the month.

[nvzqz]

Update: I now have an implementation of allocation profiling in #40. So maybe a week after that lands I'll get around to finishing async support.

[dan-da]

I'm glad to hear this is in progress. any update?

I recently converted a couple modules from sync to async. I have divan benches for them that I can't build with the new async implementations.

[nvzqz]

I'm currently prioritizing #10/#42 but I plan to support async benchmarks soon after. In the meantime, it seems folks have gotten acceptable results from just invoking block_on within the benchmark. My main motivation with async benchmarks is to move block_on overhead out of the sample time.

[king-11]

@nvzqz how does block_on work can you provide some insights I tried this it fails with panic that there is no reactor running, must be called from the context of a Tokio 1.x runtime

#[tokio::main]
async fn main() {
    divan::main();
}

#[divan::bench]
fn some_non_async_function(bencher: Bencher) {
  //
  bencher.bench(|| block_on(some_async_function()));
}

For more context some_async_function calls into tokio-postgres