go 测试代码性能实例

package test

// MakeSliceWithPreAlloc 不预分配
func MakeSliceWithoutAlloc() []int {
    var newSlice []int

    for i := 0; i < 100000; i++ {
        newSlice = append(newSlice, i)
    }

    return newSlice
}

// MakeSliceWithPreAlloc 通过预分配Slice的存储空间构造
func MakeSliceWithPreAlloc() []int {
    var newSlice []int

    newSlice = make([]int, 0, 100000)
    for i := 0; i < 100000; i++ {
        newSlice = append(newSlice, i)
    }

    return newSlice
}

package test_test
import (
    "test/test"
    "testing"
)

func BenchmarkMakeSliceWithoutAlloc(b *testing.B) {
    for i := 0; i < b.N; i++ {
        test.MakeSliceWithoutAlloc()
    }
}

func BenchmarkMakeSliceWithPreAlloc(b *testing.B) {
    for i := 0; i < b.N; i++ {
        test.MakeSliceWithPreAlloc()
    }
}