mutexとatomic比較

ベンチマーク

package atomic_test

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

func BenchmarkAtomic(b *testing.B) {
	var c uint32 = 0

	for i := 0; i < b.N; i++ {
		atomic.AddUint32(&c, 1)
		atomic.LoadUint32(&c)
	}
}

func BenchmarkMutex(b *testing.B) {
	var c uint32 = 0
	mutex := sync.RWMutex{}

	for i := 0; i < b.N; i++ {
		mutex.Lock()
		c++
		mutex.Unlock()

		mutex.RLock()
		_ = c
		mutex.RUnlock()
	}
}

結果

$ go test -run NONE -bench . -benchmem
testing: warning: no tests to run
BenchmarkAtomic-4   	100000000	        14.0 ns/op	       0 B/op	       0 allocs/op
BenchmarkMutex-4    	20000000	        60.7 ns/op	       0 B/op	       0 allocs/op
PASS
ok  	none/goexp/atomic	2.729s