4.3 benchmark

1. 使用

• bench.go

  func Fib(n int) int {
  	if n < 2 {
  		return n
  	}
  	return Fib(n-1) + Fib(n-2)
  }

• bench_test.go

  import (
  	"testing"
  )
  
  func BenchmarkFib(b *testing.B) {
  	// run the Fib function b.N times
  	for n := 0; n < b.N; n++ {
  		Fib(10)
  	}
  }

2026 注：Go 1.24+ 新写的 benchmark 也可以使用 b.Loop()；这里保留原来的 b.N 写法。

• 测试：
  • go test -bench=.

    $ go test -bench=.
    goos: windows
    goarch: amd64
    pkg: test/bench
    BenchmarkFib-6           3888090               307 ns/op
    PASS
    ok      test/bench      1.850s

  • 查看内存分配信息：go test -bench=. -benchmem

    $ go test -bench=. -benchmem
    goos: windows
    goarch: amd64
    pkg: test/bench
    BenchmarkFib-6           3897542               307 ns/op               0 B/op          0 allocs/op
    PASS
    ok      test/bench      1.858s

  • 生成CPU信息：go test -bench=. -benchmem -cpuprofile prof.cpu
    • go tool pprof bench.test.exe prof.cpu
  • 生成内存信息：go test -bench=. -benchmem -memprofile prof.mem
    • go tool pprof bench.test.exe prof.mem
  • 生成全部信息： go test -bench=".*" -benchtime=1000x -cpuprofile cpu.profile -benchmem -memprofile=mem.profile -blockprofile=block.profile -trace trace.out -mutexprofile mutex.out

2. 结果解读

go 语言 基准测试 结果解读 | 睡月花儿

3. 参考

How to write benchmarks in Go | Dave Cheney Go十大常见错误第2篇：benchmark性能测试的坑 - 掘金 benchmark 基准测试 | Go 语言高性能编程 | 极客兔兔 benchmarking - What does allocs/op and B/op mean in go benchmark? - Stack Overflow go 语言 基准测试 结果解读 | 睡月花儿 golang 性能优化分析：benchmark 结合 pprof - 九卷 - 博客园