Timing profiling?

[FrankDMartinez]

Hi. I hope everyone is having a great new year so far.

I was told by a colleague I could use this package for determining how much time is being spent in each function during an application's run. Is this correct and, if so, how? I saw nothing in the documentation which makes this clear if so.

Thanks in advance.

[davecheney]

The CPU profile is the one to start with.

If you are using linux you might also find the perf tool (comes with your linux disto, not this project) useful

[FrankDMartinez]

@davecheney Thanks for the quick reply. :-) Does the defer profile.Start().Stop() need to be placed in every function I want to time test?

[davecheney]

If you are using cpu profiling in a go test, support for generating a profile is built into the go test runner, use go test -cpuprofile=c.p

[FrankDMartinez]

Sorry. I’m not understanding what you are saying. Let me simplify. I have a project with multiple Go files and I want to know how much time The application spends in each function. Can I do that with this package and, if so, how?

[davecheney]

I think if you want to profile how much time is spent in the various parts of the program over time, start a profile at the top of main, run your program under the expected load, then control c it and investigate the profile.

if you want to micro benchmark a particular function, write a go benchmark for that function the you can use the go test -cpuprofile flag to obtain a profile of the function under test

[FrankDMartinez]

That's curious. Most profiling tools I have used allow One to run the application as a whole, perhaps with some additional aspects in order to provide the requisite functionality, and produce that information at the end. Oh, well.

[davecheney]

This package lets you turn on profiling for a section of time then emit a profile. The defer start().stop() example is just that, an example. You could do something like this

func main() {
setup()
application()
}

func application() {
stop := profile.Start()
run application
stop()
}