1 files changed, 111 insertions, 0 deletions
diff --git a/test/stress/maps.go b/test/stress/maps.go
new file mode 100644
index 000000000..d022e19ad
--- /dev/null
+++ b/test/stress/maps.go
@@ -0,0 +1,111 @@
+// Copyright 2013 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 (
+	"math/rand"
+	"runtime"
+	"sync"
+)
+
+func mapTypes() []MapType {
+	// TODO(bradfitz): bunch more map types of all different key and value types.
+	// Use reflect.MapOf and a program to generate lots of types & struct types.
+	// For now, just one:
+	return []MapType{intMapType{}}
+}
+
+type MapType interface {
+	NewMap() Map
+}
+
+type Map interface {
+	AddItem()
+	DelItem()
+	Len() int
+	GetItem()
+	RangeAll()
+}
+
+func stressMapType(mt MapType, done func()) {
+	defer done()
+	m := mt.NewMap()
+	for m.Len() < 10000 {
+		Println("map at ", m.Len())
+		if m.Len()%100 == 0 {
+			runtime.Gosched()
+		}
+		m.AddItem()
+		m.AddItem()
+		m.DelItem()
+		var wg sync.WaitGroup
+		const numGets = 10
+		wg.Add(numGets)
+		for i := 0; i < numGets; i++ {
+			go func(i int) {
+				if i&1 == 0 {
+					m.GetItem()
+				} else {
+					m.RangeAll()
+				}
+				wg.Done()
+			}(i)
+		}
+		wg.Wait()
+	}
+	for m.Len() > 0 {
+		m.DelItem()
+	}
+}
+
+type intMapType struct{}
+
+func (intMapType) NewMap() Map {
+	return make(intMap)
+}
+
+var deadcafe = []byte("\xDE\xAD\xCA\xFE")
+
+type intMap map[int][]byte
+
+func (m intMap) AddItem() {
+	s0 := len(m)
+	for len(m) == s0 {
+		key := rand.Intn(s0 + 1)
+		m[key] = make([]byte, rand.Intn(64<<10))
+	}
+}
+
+func (m intMap) DelItem() {
+	for k := range m {
+		delete(m, k)
+		return
+	}
+}
+
+func (m intMap) GetItem() {
+	key := rand.Intn(len(m))
+	if s, ok := m[key]; ok {
+		copy(s, deadcafe)
+	}
+}
+
+func (m intMap) Len() int { return len(m) }
+
+func (m intMap) RangeAll() {
+	for _ = range m {
+	}
+}
+
+func stressMaps() {
+	for {
+		var wg sync.WaitGroup
+		for _, mt := range mapTypes() {
+			wg.Add(1)
+			go stressMapType(mt, wg.Done)
+		}
+		wg.Wait()
+	}
+}