Parallel Malloc Test for Go

mallocparallel_test.go

// +build ignore

// malloc test for false sharing


package main

import (
	"flag"
	"runtime"
	"sync"
	"testing"
)

var (
	procs int
	allocsize int
)

func init() {
	flag.IntVar(&procs, "procs", 1, "Value to set GOMAXPROCS")
	flag.IntVar(&allocsize, "size", 16, "Size of block to allocate")
}

func do_thread(niters int, wg *sync.WaitGroup) {
	runtime.LockOSThread()
	for iter := 0; iter < niters; iter++ {
		b := runtime.Alloc(uintptr(allocsize))
		// Write a bunch to b.
		for i, _ := range b {
			b[i] = byte(i)
		}
		runtime.Free(b)
	}
	wg.Done()
	runtime.UnlockOSThread()
}

func BenchmarkSharing(b *testing.B) {
	runtime.GC()                    // clean up garbage from init
	oldprocs := runtime.GOMAXPROCS(procs)

	var wg sync.WaitGroup
	for i := 0; i < procs; i++ {
		wg.Add(1)
		go do_thread(b.N / procs, &wg)
	}
	wg.Wait()

        runtime.GOMAXPROCS(oldprocs)
}

output

$ go test mallocparallel_test.go 
# command-line-arguments
./mallocparallel_test.go:28: undefined: runtime.Alloc
./mallocparallel_test.go:33: undefined: runtime.Free
FAIL	command-line-arguments [build failed]