Benchmark: sync.RWMutex vs atomic.Value

atomutex_test.go

/*

Benchmark_RWMutex-4            	100000000	        18.1 ns/op
Benchmark_Atomic-4             	200000000	         8.01 ns/op
Benchmark_RWMutex_parallel-4   	30000000	        46.7 ns/op
Benchmark_Atomic_parallel-4    	1000000000	         2.61 ns/op

*/
package main

import (
	"sync"
	"sync/atomic"
	"testing"
)

func Benchmark_RWMutex(b *testing.B) {
	var lock sync.RWMutex
	m := map[int]int{1: 2}

	for i := 0; i < b.N; i++ {
		lock.RLock()
		_ = m[1]
		lock.RUnlock()
	}
}

func Benchmark_Atomic(b *testing.B) {
	var ptr atomic.Value
	ptr.Store(map[int]int{1: 2})

	for i := 0; i < b.N; i++ {
		m := ptr.Load().(map[int]int)
		_ = m[1]
	}
}

func Benchmark_RWMutex_parallel(b *testing.B) {
	var lock sync.RWMutex
	m := map[int]int{1: 2}

	b.RunParallel(func(pb *testing.PB) {
		for pb.Next() {
			lock.RLock()
			_ = m[1]
			lock.RUnlock()
		}
	})
}

func Benchmark_Atomic_parallel(b *testing.B) {
	var ptr atomic.Value
	ptr.Store(map[int]int{1: 2})

	b.RunParallel(func(pb *testing.PB) {
		for pb.Next() {
			m := ptr.Load().(map[int]int)
			_ = m[1]
		}
	})
}

atomic/mutex offen use in concurrent
if change test to goroutine in loop - situation changing

BenchmarkLockMultiply
BenchmarkLockMultiply-8     	 5213317	       232.3 ns/op
BenchmarkAtomicMultiply
BenchmarkAtomicMultiply-8   	 5166256	       230.2 ns/op
BenchmarkLockOne
BenchmarkLockOne-8          	104955392	        11.45 ns/op
BenchmarkAtomicOne
BenchmarkAtomicOne-8        	249697118	         4.790 ns/op