Add CPU profiler section

guide/cpu-max-stack-depth.go

@@ -0,0 +1,37 @@
+// +build ignore
+
+package main
+
+import (
+	"os"
+	"runtime/pprof"
+)
+
+func main() {
+	pprof.StartCPUProfile(os.Stdout)
+	defer pprof.StopCPUProfile()
+
+	belowLimit()
+	aboveLimit()
+}
+
+func belowLimit() {
+	atDepth(32, cpuHog)
+}
+
+func aboveLimit() {
+	atDepth(64, cpuHog)
+}
+
+func cpuHog() {
+	for i := 0; i < 5000*1000*1000; i++ {
+	}
+}
+
+func atDepth(n int, fn func()) {
+	if n > 0 {
+		atDepth(n-1, fn)
+	} else {
+		fn()
+	}
+}