Исходники и презентации

lessons/sync_primitives/false_sharing/perf_test.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"testing"
+)
+
+// go test -bench=. perf_test.go
+
+type MutexCounter struct {
+	value int32
+	mutex sync.Mutex
+}
+
+func (c *MutexCounter) Increment(int) {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	c.value++
+}
+
+func (c *MutexCounter) Get() int32 {
+	c.mutex.Lock()
+	defer c.mutex.Unlock()
+	return c.value
+}
+
+type AtomicCounter struct {
+	value atomic.Int32
+}
+
+func (c *AtomicCounter) Increment(int) {
+	c.value.Add(1)
+}
+
+func (c *AtomicCounter) Get() int32 {
+	return c.value.Load()
+}
+
+type ShardedAtomicCounter struct {
+	shards [10]AtomicCounter
+}
+
+func (c *ShardedAtomicCounter) Increment(idx int) {
+	c.shards[idx].value.Add(1)
+}
+
+func (c *ShardedAtomicCounter) Get() int32 {
+	var value int32
+	for idx := 0; idx < 10; idx++ {
+		value += c.shards[idx].Get()
+	}
+
+	return value
+}
+
+func BenchmarkAtomicCounter(b *testing.B) {
+	wg := sync.WaitGroup{}
+	wg.Add(runtime.NumCPU())
+
+	counter := MutexCounter{}
+	for i := 0; i < runtime.NumCPU(); i++ {
+		go func(idx int) {
+			defer wg.Done()
+			for j := 0; j < b.N; j++ {
+				counter.Increment(idx)
+			}
+		}(i)
+	}
+
+	wg.Wait()
+}