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