[GnoVM] Request: add simple way to get VM cycles used on specific call

[leohhhn]

Description

It would be great if we can have a simple way to see how many cycles a specific call has spent. For example, adding a --measure-cycles flag to gnokey would be an idea to start with.

[deelawn]

The gas used should be a function of the cycles spent. Would an end user care how many cycles are used?

[leohhhn]

Are we sure that gas will be a function of cycles used? 😄

In any case, might be cool for debugging/metrics/stress testing.

[deelawn]

Yes, it will be. Is your proposal to return VM cycles used like we return gas used when sending transactions via gnokey?

[leohhhn]

Correct!

[leohhhn]

For reference - it seems that the gno test binary already has an option for displaying cycles along with some other metrics - gno test . -v -print-runtime-metrics. This is an alright workaround, ie you can make a test simply calling the function you want to check cycles for:

func TestC(t *testing.T) {
	Render("")
}

Still, I would like to see a -debug or -mertrics option when using gnokey. WDYT?

[deelawn]

I'm not sure I'm convinced. Maybe someone else can chime in on this.