如何记录测试时间

I wrote two functions and now I would love to find out, which of them is faster. How can I find it out, which one is faster?

How can I find out by testing, which one is faster? Do go provide a timer for that?

Even better, Go provides a built in benchmark and testing functionality!

Create a file named something_test.go (must have the _test part).

func BenchmarkFunc1(b *testing.B) {
    for i := 0; i < b.N; i++ {
        _ = Func1()
    }
}

func BenchmarkFunc2(b *testing.B) {
    for i := 0; i < b.N; i++ {
        _ = Func2()
    }
}

Then simply run: go test -bench=. -benchmem

It will print how long each function took and memory usage / allocations.

Ref:

• http://golang.org/pkg/testing/
• http://dave.cheney.net/2013/06/30/how-to-write-benchmarks-in-go

You could write a benchmark for each function.

See for instance "How to write benchmarks in Go"

// from source_test.go
func BenchmarkFunction1(b *testing.B) {
        // run the Function1 function b.N times
        for n := 0; n < b.N; n++ {
                Function1(10)
        }
}

Repeat for Function2 and check the results with go test -bench=.