消息队列高手课 Mutex,CAS&FAA作业程序

balance_test.go

package balance

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

const MaxCount = 10000

func transfer_Mutex(balance *int32, amount int32, lock *sync.Mutex) {
	lock.Lock()
	defer lock.Unlock()
	*balance = *balance + amount
}

func balance_Mutex() int32 {
	wg := &sync.WaitGroup{}
	lock := &sync.Mutex{}
	balance := int32(0)
	for i := 0; i < MaxCount; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			transfer_Mutex(&balance, 1, lock)
		}()
	}
	wg.Wait()
	//fmt.Println("Balance: ", balance)
	return balance
}

func transfer_CAS(balance *int32, amount int32) {
	for {
		old := atomic.LoadInt32(balance)
		new := old + amount
		if atomic.CompareAndSwapInt32(balance, old, new) {
			break
		}
		runtime.Gosched()
	}
}
func balance_CAS() int32 {
	balance := int32(0)
	wg := &sync.WaitGroup{}

	for i := 0; i < MaxCount; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			transfer_CAS(&balance, 1)
		}()
	}
	wg.Wait()
	//fmt.Println("Balance: ", balance)
	return balance
}

func transfer_FAA(balance *int32, amount int32) {
	atomic.AddInt32(balance, amount)
}
func balance_FAA() int32 {
	balance := int32(0)
	wg := &sync.WaitGroup{}

	for i := 0; i < MaxCount; i++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			transfer_FAA(&balance, 1)
		}()
	}
	wg.Wait()
	//fmt.Println("Balance: ", balance)
	return balance
}

func Test_balance_Mutex(t *testing.T) {
	for i := 0; i < 1000; i++ {
		if balance_Mutex() != MaxCount {
			t.Fail()
		}
	}
}

func Benchmark_balance_Mutex(b *testing.B) {
	for i := 0; i < b.N; i++ {
		if balance_Mutex() != MaxCount {
			b.Fail()
		}
	}
}

func Test_balance_CAS(t *testing.T) {
	for i := 0; i < 1000; i++ {
		if balance_CAS() != MaxCount {
			t.Fail()
		}
	}
}

func Benchmark_balance_CAS(b *testing.B) {
	for i := 0; i < b.N; i++ {
		if balance_CAS() != MaxCount {
			b.Fail()
		}
	}
}

func Test_balance_FAA(t *testing.T) {
	for i := 0; i < 1000; i++ {
		if balance_FAA() != MaxCount {
			t.Fail()
		}
	}
}

func Benchmark_balance_FAA(b *testing.B) {
	for i := 0; i < b.N; i++ {
		if balance_FAA() != MaxCount {
			b.Fail()
		}
	}
}

/*
Benchmark_balance_Mutex-12    	     300	   4262947 ns/op
Benchmark_balance_CAS-12      	     300	   4016430 ns/op
Benchmark_balance_FAA-12      	     500	   3965553 ns/op
*/