Golang函数指针和闭包的性能优化技巧

package main

import "fmt"

// 定义一个带有函数参数的结构
type Processor struct {
    processFn func(int) int
}

// 优化后的 Processor，使用直接函数调用
type OptimizedProcessor struct {
    f func(int) int
}

// 创建一个带有匿名函数指针的 Processor
func newProcessorWithAnonFn() *Processor {
    return &Processor{
        processFn: func(x int) int { return x * x },
    }
}

// 创建一个带有已命名函数的 Processor
func newProcessorWithNamedFn() *Processor {
    return &Processor{
        processFn: multiply,
    }
}

// 创建一个带有已命名函数的 OptimizedProcessor
func newOptimizedProcessor() *OptimizedProcessor {
    return &OptimizedProcessor{
        f: multiply,
    }
}

// 一个已命名的函数
func multiply(x int) int { return x * x }

func main() {
    // 评估处理器的性能
    anonProc := newProcessorWithAnonFn()
    namedProc := newProcessorWithNamedFn()
    optimizedProc := newOptimizedProcessor()

    iterations := 1000000

    anonStart := time.Now()
    for i := 0; i < iterations; i++ {
        anonProc.processFn(i)
    }
    anonDuration := time.Since(anonStart)

    namedStart := time.Now()
    for i := 0; i < iterations; i++ {
        namedProc.processFn(i)
    }
    namedDuration := time.Since(namedStart)

    optimizedStart := time.Now()
    for i := 0; i < iterations; i++ {
        optimizedProc.f(i)
    }
    optimizedDuration := time.Since(optimizedStart)

    // 输出性能结果
    fmt.Printf("Processor with anonymous function pointer: %s\n", anonDuration)
    fmt.Printf("Processor with named function: %s\n", namedDuration)
    fmt.Printf("Optimized processor with direct function call: %s\n", optimizedDuration)
}