Golang切片追加与分配性能

To make slice append operation faster we need to allocate enough capacity. There's two ways to append slice, Here is the code:

func BenchmarkSliceAppend(b *testing.B) {
    a := make([]int, 0, b.N)
    for i := 0; i < b.N; i++ {
        a = append(a, i)
    }
}

func BenchmarkSliceSet(b *testing.B) {
    a := make([]int, b.N)
    for i := 0; i < b.N; i++ {
        a[i] = i
    }
}

And the result is:

BenchmarkSliceAppend-4 200000000 7.87 ns/op 8 B/op 0 allocs/op

BenchmarkSliceSet-4 300000000 5.76 ns/op 8 B/op

a[i] = ia = append(a, i)