1 files changed, 95 insertions, 0 deletions
diff --git a/test/bench/garbage/tree2.go b/test/bench/garbage/tree2.go
new file mode 100644
index 0000000..a70a106
--- /dev/null
+++ b/test/bench/garbage/tree2.go
@@ -0,0 +1,95 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"runtime"
+	"runtime/pprof"
+	"time"
+	"unsafe"
+)
+
+const BranchingFactor = 4
+
+type Object struct {
+	child [BranchingFactor]*Object
+}
+
+var (
+	cpus       = flag.Int("cpus", 1, "number of cpus to use")
+	heapsize   = flag.Int64("heapsize", 100*1024*1024, "size of the heap in bytes")
+	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
+
+	lastPauseNs uint64 = 0
+	lastFree    uint64 = 0
+	heap        *Object
+	calls       [20]int
+	numobjects  int64
+	memstats    runtime.MemStats
+)
+
+func buildHeap() {
+	objsize := int64(unsafe.Sizeof(Object{}))
+	heap, _ = buildTree(float64(objsize), float64(*heapsize), 0)
+	fmt.Printf("*** built heap: %.0f MB; (%d objects * %d bytes)\n",
+		float64(*heapsize)/1048576, numobjects, objsize)
+}
+
+func buildTree(objsize, size float64, depth int) (*Object, float64) {
+	calls[depth]++
+	x := &Object{}
+	numobjects++
+	subtreeSize := (size - objsize) / BranchingFactor
+	alloc := objsize
+	for i := 0; i < BranchingFactor && alloc < size; i++ {
+		c, n := buildTree(objsize, subtreeSize, depth+1)
+		x.child[i] = c
+		alloc += n
+	}
+	return x, alloc
+}
+
+func gc() {
+	runtime.GC()
+	runtime.ReadMemStats(&memstats)
+	pause := memstats.PauseTotalNs
+	inuse := memstats.Alloc
+	free := memstats.TotalAlloc - inuse
+	fmt.Printf("gc pause: %8.3f ms; collect: %8.0f MB; heapsize: %8.0f MB\n",
+		float64(pause-lastPauseNs)/1e6,
+		float64(free-lastFree)/1048576,
+		float64(inuse)/1048576)
+	lastPauseNs = pause
+	lastFree = free
+}
+
+func main() {
+	flag.Parse()
+	buildHeap()
+	runtime.GOMAXPROCS(*cpus)
+	runtime.ReadMemStats(&memstats)
+	lastPauseNs = memstats.PauseTotalNs
+	lastFree = memstats.TotalAlloc - memstats.Alloc
+	if *cpuprofile != "" {
+		f, err := os.Create(*cpuprofile)
+		if err != nil {
+			log.Fatal(err)
+		}
+		pprof.StartCPUProfile(f)
+		defer pprof.StopCPUProfile()
+	}
+	const N = 10
+	var t0 time.Time
+	for i := 0; i < N; i++ {
+		t0 = time.Now()
+		gc()
+	}
+	// Standard gotest benchmark output, collected by build dashboard.
+	gcstats("BenchmarkTree2", N, time.Now().Sub(t0))
+}