cpuburn: Utility to load all cores

Debian's cpuburn was removed from the distribution.

bin/cpuburn.go

+// #!/usr/bin/env -S go run
+// cpuburn loads all cpu cores.
+//
+// Reason for this program: cpuburn Debian package got bitrotted.
+//
+// Note: one can also simulate 1 core burn by `yes >/dev/null`.
+package main
+
+import (
+	"runtime"
+	"sync"
+)
+
+func work() {
+	var i [3]int
+	var x [3]float64
+
+	i[0], i[1], i[2] = 1, 2, 3
+	x[0], x[1], x[2] = 3.14, 2.17, 1.61
+
+	for j := 0; ; j++ {
+		// ALU
+		kp := j % 3
+		k := (kp+1) % 3
+
+		// FPU
+		x[k] += float64(i[kp]) * x[kp]
+	}
+}
+
+func main() {
+	wg := sync.WaitGroup{}
+	njob := runtime.NumCPU()
+
+	for i := 0; i < njob; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			work()
+		}()
+	}
+
+	wg.Wait()
+}