Add await-call-tree benchmark

[tmandry]

To go with rust-lang/rust#65293 which fixes rust-lang/rust#65147. Locally I'm seeing a ~37x decrease in instruction count on check.

r? @Mark-Simulacrum

[Mark-Simulacrum]

Can you see that this has comparable instruction count / runtime with some of the other benchmarks? In particular e.g. deep-vector is probably a good comparison point.

[tmandry]

Can you see that this has comparable instruction count / runtime with some of the other benchmarks? In particular e.g. deep-vector is probably a good comparison point.

A check run goes from 150B instructions before the fix to only 233 million instructions after, while deep-vector is about 5B instructions.

A debug run goes from 256B to 107B instructions, while deep-vector is only about 8B.

I'm currently running a few more for comparison, not sure if this answers your question or not.

[Mark-Simulacrum]

It would be good to lower the nesting such that this is about the same run time as that benchmark; this is too long for our use case probably.

[tmandry]

It would be good to lower the nesting such that this is about the same run time as that benchmark; this is too long for our use case probably.

The check run time is only ~15 seconds before the fix; after it's about 0.52 seconds.
For debug builds it's 25 seconds before, 11 seconds after.
Is that too long?

[tmandry]

Removing two levels of nesting gets us to <1s on debug builds (after fix) while showing a -94% reduction in instruction count on check, so going with that.

[Mark-Simulacrum]

Yes, most of our benchmarks are around 1-2 seconds long. 30 seconds is getting into script-servo territory, which is the longest benchmark today I believe; we run each benchmark 3 times per "type" of which there are 3 at minimum (clean, baseline incr, clean incr, see bottom of a compare page for more details); and then for each check/opt/debug -- all in all, that's 27 times at minimum pretty much so a 30 second benchmark would add ~15 minutes of runtime which is quite a lot :)

[Mark-Simulacrum]

Removing two levels of nesting gets us to <1s on debug builds (after fix) while showing a -94% reduction in instruction count on check, so going with that.

This sounds perfect, after fix is pretty much all that matters here I think.

I'll try to get this merged tomorrow.

[tmandry]

I'll try to get this merged tomorrow.

Great, thanks! Once it is merged can I kick off a rust-timer run immediately, or do I need to wait for the bot to be updated?

[Mark-Simulacrum]

No, I'll be re-deploying the collector pretty much immediately upon merging so you'll not need to wait at all (well, give me like ~5 minutes :)

[tmandry]

Perfect. Feel free to kick off a run on rust-lang/rust#65293 if I'm not around.

[nnethercote]

+1 for updating the docs!

[tmandry]

I just realized the 9 is no longer correct, removing it :)