Golang Memory Usage (like vmstat)

main.go

import (
  "fmt"
  "time
)

func main() {
	fmt.Println("Hello, world")
	
	go func() {
		t := time.NewTicker(3 * time.Second) // 3秒おき
		for {
			select {
			case <-t.C:
				PrintMemUsage()
			}
		}
		t.Stop() // タイマ停止
	}()

	for {
		// loop
	}
	
	// Force GC to clear up, should see a memory drop
	runtime.GC()
	PrintMemUsage()
}

// PrintMemUsage outputs the current, total and OS memory being used. As well as the number
// of garage collection cycles completed.
func PrintMemUsage() {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)
	// For info on each, see: https://golang.org/pkg/runtime/#MemStats
	fmt.Printf("Alloc = %v MiB", bToMb(m.Alloc))
	fmt.Printf("\tTotalAlloc = %v MiB", bToMb(m.TotalAlloc))
	fmt.Printf("\tSys = %v MiB", bToMb(m.Sys))
	fmt.Printf("\tNumGC = %v\n", m.NumGC)
}

func bToMb(b uint64) uint64 {
	return b / 1024 / 1024
}