race conditions

Author: GoesToEleven

000_temp/52-race-condition/01/main.go

@@ -0,0 +1,34 @@
+package _1
+
+import (
+	"fmt"
+	"sync"
+	"runtime"
+)
+
+var counter = 0
+var mu sync.Mutex
+
+func main() {
+
+
+	const gs = 4
+	var wg sync.WaitGroup
+	wg.Add(gs)
+
+	for i := 0; i < gs; i++ {
+		go func() {
+			mu.Lock()
+			v := counter
+			// 			time.Sleep(time.Second * 2)
+			runtime.Gosched() // tells runtime to yield processor to other goroutine
+			v++
+			counter = v
+			mu.Unlock()
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+
+	fmt.Println(counter)
+}

000_temp/52-race-condition/02/main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"fmt"
+	"runtime"
+	"sync"
+)
+
+var wg sync.WaitGroup
+var counter int
+
+func main() {
+	fmt.Println(runtime.NumCPU())
+
+	const gs = 100
+	wg.Add(gs)
+
+	for i := 0; i < gs; i++ {
+		go func() {
+			v := counter
+			// time.Sleep(time.Second)
+			runtime.Gosched()
+			v++
+			counter = v
+			wg.Done()
+		}()
+		fmt.Println(runtime.NumGoroutine())
+		fmt.Println(runtime.NumCPU())
+	}
+	fmt.Println(runtime.NumGoroutine())
+	wg.Wait()
+	fmt.Println(counter)
+}

000_temp/52-race-condition/03_race/main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"fmt"
+	"runtime"
+	"sync"
+)
+
+func main() {
+	fmt.Println("CPUs:", runtime.NumCPU())
+	fmt.Println("Goroutines:", runtime.NumGoroutine())
+
+	counter := 0
+
+	const gs = 100
+	var wg sync.WaitGroup
+	wg.Add(gs)
+
+	for i := 0; i < gs; i++ {
+		go func() {
+			v := counter
+			// time.Sleep(time.Second)
+			runtime.Gosched()
+			v++
+			counter = v
+			wg.Done()
+		}()
+		fmt.Println("Goroutines:", runtime.NumGoroutine())
+	}
+	wg.Wait()
+	fmt.Println("Goroutines:", runtime.NumGoroutine())
+	fmt.Println("count:", counter)
+}

000_temp/52-race-condition/04_mutex/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"fmt"
+	"runtime"
+	"sync"
+)
+
+func main() {
+	fmt.Println("CPUs:", runtime.NumCPU())
+	fmt.Println("Goroutines:", runtime.NumGoroutine())
+
+	counter := 0
+
+	const gs = 100
+	var wg sync.WaitGroup
+	wg.Add(gs)
+
+	var mu sync.Mutex
+
+	for i := 0; i < gs; i++ {
+		go func() {
+			mu.Lock()
+			v := counter
+			// time.Sleep(time.Second)
+			runtime.Gosched()
+			v++
+			counter = v
+			mu.Unlock()
+			wg.Done()
+		}()
+		fmt.Println("Goroutines:", runtime.NumGoroutine())
+	}
+	wg.Wait()
+	fmt.Println("Goroutines:", runtime.NumGoroutine())
+	fmt.Println("count:", counter)
+}

000_temp/52-race-condition/05_atomic/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"fmt"
+	"runtime"
+	"sync"
+)
+
+func main() {
+	fmt.Println("CPUs:", runtime.NumCPU())
+	fmt.Println("Goroutines:", runtime.NumGoroutine())
+
+	counter := 0
+
+	const gs = 100
+	var wg sync.WaitGroup
+	wg.Add(gs)
+
+	var mu sync.Mutex
+
+	for i := 0; i < gs; i++ {
+		go func() {
+			mu.Lock()
+			v := counter
+			// time.Sleep(time.Second)
+			runtime.Gosched()
+			v++
+			counter = v
+			mu.Unlock()
+			wg.Done()
+		}()
+		fmt.Println("Goroutines:", runtime.NumGoroutine())
+	}
+	wg.Wait()
+	fmt.Println("Goroutines:", runtime.NumGoroutine())
+	fmt.Println("count:", counter)
+}