Use sudo --non-interactive in at_exit to not hang

[alanwu-shopify-inc]

I noticed that ruby-bench hangs after a long enough benchmarking session. Turns out it was sudo trying to ask for with quiet: true. Since it may hang trying to ask for input during exit, let's use --non-interactive to opportunistically re-enable turbo boost.

[k0kubun]

It would leave turbo boost in a random state, depending on how long it took to run benchmarks, and run_benchmarks.rb would exit abnormally.

At this point, can we just drop the at_exit hook? I prefer a deterministic behavior and not failing the command for re-enabling turbo boost.

[alanwu-shopify-inc]

It would leave turbo boost in a random state, depending on how long it took to run benchmarks, and run_benchmarks.rb would exit abnormally.

All that is not new with this change, just that before this change it would also hang before exiting abnormally

At this point, can we just drop the at_exit hook? I prefer a deterministic behavior and not failing the command for re-enabling turbo boost.

It seems still useful for short runs, though. It's also nice to not have to figure out the command to restore turbo boost manually, or have a script ready that does it.

[alanwu-shopify-inc]

Related to this, maybe we want to flip it and have --no-sudo by default. I think the at_exit hook is important if it turns off turbo boost etc by default.

[eregon]

What's the reason to use quiet: true BTW? That seems the source of "it hangs and not clear why".

Though I agree hanging/waiting for input after a benchmark run is done is not great.

Maybe a solution would be to spawn a subprocess that runs under sudo, so it keeps root permissions during the whole run and restores the state without needing to ask for the sudo password again.

[alanwu-shopify-inc]

I'm not sure why it uses quiet either. Dropping quiet seems another viable path. It's ugly, but probably not good to hide a sudo call either.

[k0kubun]

It would leave turbo boost in a random state, depending on how long it took to run benchmarks, and run_benchmarks.rb would exit abnormally.

All that is not new with this change, just that before this change it would also hang before exiting abnormally

I'm not sure if I follow. It would not randomly give up on restoring the state or exit abnormally after the password input.

What's the reason to use quiet: true BTW?

quiet: true suppresses two things:

1. out: File::NULL, err: File::NULL
2. puts("+ #{command}")

I think we want to drop (1) from the sudo command, whether we use --non-interactive or not. If we decide to use --non-interactive, exiting abnormally without printing sudo: a password is required seems pretty bad.

On the other hand, I don't want to see (2) for this sudo command in most cases. However, if we can print it only when (we don't use --non-interactive and) it asks for password, it might be useful.