Correctly measure time duration in Go

Question

What is the correct way to precisely measure a time duration in Go? Most application just use the standard time package and the following approach:

var start         


        

Answer 1

For Go 1.8 and before, the correct timing function is not inside the time package, but instead in the runtime package:

func nanotime() int64

In order to correctly measure execution time, the following procedure should be used:

var startTime = runtime.nanotime()
doSomeHardWork()
var duration = runtime.nanotime() - startTime

Unfortunately, the method itself is not documented very well. It emerged in this issue after a long discussion if it was really neccessary. For Go 1.9 and newer, refer to Kenny Grant's answer.