runtime: expose memory stats

src/examples/memstats/memstats.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"math/rand"
+	"runtime"
+	"time"
+)
+
+func main() {
+
+	ms := runtime.MemStats{}
+
+	for {
+		escapesToHeap()
+		runtime.ReadMemStats(&ms)
+		println("Heap before GC. Used: ", ms.HeapInuse, " Free: ", ms.HeapIdle, " Meta: ", ms.GCSys)
+		runtime.GC()
+		runtime.ReadMemStats(&ms)
+		println("Heap after  GC. Used: ", ms.HeapInuse, " Free: ", ms.HeapIdle, " Meta: ", ms.GCSys)
+		time.Sleep(5 * time.Second)
+	}
+
+}
+
+func escapesToHeap() {
+	n := rand.Intn(100)
+	println("Doing ", n, " iterations")
+	for i := 0; i < n; i++ {
+		s := make([]byte, i)
+		_ = append(s, 42)
+	}
+}