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-rw-r--r--src/expvar/expvar.go367
-rw-r--r--src/expvar/expvar_test.go601
2 files changed, 968 insertions, 0 deletions
diff --git a/src/expvar/expvar.go b/src/expvar/expvar.go
new file mode 100644
index 0000000..13b5c99
--- /dev/null
+++ b/src/expvar/expvar.go
@@ -0,0 +1,367 @@
+// Copyright 2009 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 expvar provides a standardized interface to public variables, such
+// as operation counters in servers. It exposes these variables via HTTP at
+// /debug/vars in JSON format.
+//
+// Operations to set or modify these public variables are atomic.
+//
+// In addition to adding the HTTP handler, this package registers the
+// following variables:
+//
+// cmdline os.Args
+// memstats runtime.Memstats
+//
+// The package is sometimes only imported for the side effect of
+// registering its HTTP handler and the above variables. To use it
+// this way, link this package into your program:
+// import _ "expvar"
+//
+package expvar
+
+import (
+ "encoding/json"
+ "fmt"
+ "log"
+ "math"
+ "net/http"
+ "os"
+ "runtime"
+ "sort"
+ "strconv"
+ "strings"
+ "sync"
+ "sync/atomic"
+)
+
+// Var is an abstract type for all exported variables.
+type Var interface {
+ // String returns a valid JSON value for the variable.
+ // Types with String methods that do not return valid JSON
+ // (such as time.Time) must not be used as a Var.
+ String() string
+}
+
+// Int is a 64-bit integer variable that satisfies the Var interface.
+type Int struct {
+ i int64
+}
+
+func (v *Int) Value() int64 {
+ return atomic.LoadInt64(&v.i)
+}
+
+func (v *Int) String() string {
+ return strconv.FormatInt(atomic.LoadInt64(&v.i), 10)
+}
+
+func (v *Int) Add(delta int64) {
+ atomic.AddInt64(&v.i, delta)
+}
+
+func (v *Int) Set(value int64) {
+ atomic.StoreInt64(&v.i, value)
+}
+
+// Float is a 64-bit float variable that satisfies the Var interface.
+type Float struct {
+ f uint64
+}
+
+func (v *Float) Value() float64 {
+ return math.Float64frombits(atomic.LoadUint64(&v.f))
+}
+
+func (v *Float) String() string {
+ return strconv.FormatFloat(
+ math.Float64frombits(atomic.LoadUint64(&v.f)), 'g', -1, 64)
+}
+
+// Add adds delta to v.
+func (v *Float) Add(delta float64) {
+ for {
+ cur := atomic.LoadUint64(&v.f)
+ curVal := math.Float64frombits(cur)
+ nxtVal := curVal + delta
+ nxt := math.Float64bits(nxtVal)
+ if atomic.CompareAndSwapUint64(&v.f, cur, nxt) {
+ return
+ }
+ }
+}
+
+// Set sets v to value.
+func (v *Float) Set(value float64) {
+ atomic.StoreUint64(&v.f, math.Float64bits(value))
+}
+
+// Map is a string-to-Var map variable that satisfies the Var interface.
+type Map struct {
+ m sync.Map // map[string]Var
+ keysMu sync.RWMutex
+ keys []string // sorted
+}
+
+// KeyValue represents a single entry in a Map.
+type KeyValue struct {
+ Key string
+ Value Var
+}
+
+func (v *Map) String() string {
+ var b strings.Builder
+ fmt.Fprintf(&b, "{")
+ first := true
+ v.Do(func(kv KeyValue) {
+ if !first {
+ fmt.Fprintf(&b, ", ")
+ }
+ fmt.Fprintf(&b, "%q: %v", kv.Key, kv.Value)
+ first = false
+ })
+ fmt.Fprintf(&b, "}")
+ return b.String()
+}
+
+// Init removes all keys from the map.
+func (v *Map) Init() *Map {
+ v.keysMu.Lock()
+ defer v.keysMu.Unlock()
+ v.keys = v.keys[:0]
+ v.m.Range(func(k, _ interface{}) bool {
+ v.m.Delete(k)
+ return true
+ })
+ return v
+}
+
+// addKey updates the sorted list of keys in v.keys.
+func (v *Map) addKey(key string) {
+ v.keysMu.Lock()
+ defer v.keysMu.Unlock()
+ // Using insertion sort to place key into the already-sorted v.keys.
+ if i := sort.SearchStrings(v.keys, key); i >= len(v.keys) {
+ v.keys = append(v.keys, key)
+ } else if v.keys[i] != key {
+ v.keys = append(v.keys, "")
+ copy(v.keys[i+1:], v.keys[i:])
+ v.keys[i] = key
+ }
+}
+
+func (v *Map) Get(key string) Var {
+ i, _ := v.m.Load(key)
+ av, _ := i.(Var)
+ return av
+}
+
+func (v *Map) Set(key string, av Var) {
+ // Before we store the value, check to see whether the key is new. Try a Load
+ // before LoadOrStore: LoadOrStore causes the key interface to escape even on
+ // the Load path.
+ if _, ok := v.m.Load(key); !ok {
+ if _, dup := v.m.LoadOrStore(key, av); !dup {
+ v.addKey(key)
+ return
+ }
+ }
+
+ v.m.Store(key, av)
+}
+
+// Add adds delta to the *Int value stored under the given map key.
+func (v *Map) Add(key string, delta int64) {
+ i, ok := v.m.Load(key)
+ if !ok {
+ var dup bool
+ i, dup = v.m.LoadOrStore(key, new(Int))
+ if !dup {
+ v.addKey(key)
+ }
+ }
+
+ // Add to Int; ignore otherwise.
+ if iv, ok := i.(*Int); ok {
+ iv.Add(delta)
+ }
+}
+
+// AddFloat adds delta to the *Float value stored under the given map key.
+func (v *Map) AddFloat(key string, delta float64) {
+ i, ok := v.m.Load(key)
+ if !ok {
+ var dup bool
+ i, dup = v.m.LoadOrStore(key, new(Float))
+ if !dup {
+ v.addKey(key)
+ }
+ }
+
+ // Add to Float; ignore otherwise.
+ if iv, ok := i.(*Float); ok {
+ iv.Add(delta)
+ }
+}
+
+// Delete deletes the given key from the map.
+func (v *Map) Delete(key string) {
+ v.keysMu.Lock()
+ defer v.keysMu.Unlock()
+ i := sort.SearchStrings(v.keys, key)
+ if i < len(v.keys) && key == v.keys[i] {
+ v.keys = append(v.keys[:i], v.keys[i+1:]...)
+ v.m.Delete(key)
+ }
+}
+
+// Do calls f for each entry in the map.
+// The map is locked during the iteration,
+// but existing entries may be concurrently updated.
+func (v *Map) Do(f func(KeyValue)) {
+ v.keysMu.RLock()
+ defer v.keysMu.RUnlock()
+ for _, k := range v.keys {
+ i, _ := v.m.Load(k)
+ f(KeyValue{k, i.(Var)})
+ }
+}
+
+// String is a string variable, and satisfies the Var interface.
+type String struct {
+ s atomic.Value // string
+}
+
+func (v *String) Value() string {
+ p, _ := v.s.Load().(string)
+ return p
+}
+
+// String implements the Var interface. To get the unquoted string
+// use Value.
+func (v *String) String() string {
+ s := v.Value()
+ b, _ := json.Marshal(s)
+ return string(b)
+}
+
+func (v *String) Set(value string) {
+ v.s.Store(value)
+}
+
+// Func implements Var by calling the function
+// and formatting the returned value using JSON.
+type Func func() interface{}
+
+func (f Func) Value() interface{} {
+ return f()
+}
+
+func (f Func) String() string {
+ v, _ := json.Marshal(f())
+ return string(v)
+}
+
+// All published variables.
+var (
+ vars sync.Map // map[string]Var
+ varKeysMu sync.RWMutex
+ varKeys []string // sorted
+)
+
+// Publish declares a named exported variable. This should be called from a
+// package's init function when it creates its Vars. If the name is already
+// registered then this will log.Panic.
+func Publish(name string, v Var) {
+ if _, dup := vars.LoadOrStore(name, v); dup {
+ log.Panicln("Reuse of exported var name:", name)
+ }
+ varKeysMu.Lock()
+ defer varKeysMu.Unlock()
+ varKeys = append(varKeys, name)
+ sort.Strings(varKeys)
+}
+
+// Get retrieves a named exported variable. It returns nil if the name has
+// not been registered.
+func Get(name string) Var {
+ i, _ := vars.Load(name)
+ v, _ := i.(Var)
+ return v
+}
+
+// Convenience functions for creating new exported variables.
+
+func NewInt(name string) *Int {
+ v := new(Int)
+ Publish(name, v)
+ return v
+}
+
+func NewFloat(name string) *Float {
+ v := new(Float)
+ Publish(name, v)
+ return v
+}
+
+func NewMap(name string) *Map {
+ v := new(Map).Init()
+ Publish(name, v)
+ return v
+}
+
+func NewString(name string) *String {
+ v := new(String)
+ Publish(name, v)
+ return v
+}
+
+// Do calls f for each exported variable.
+// The global variable map is locked during the iteration,
+// but existing entries may be concurrently updated.
+func Do(f func(KeyValue)) {
+ varKeysMu.RLock()
+ defer varKeysMu.RUnlock()
+ for _, k := range varKeys {
+ val, _ := vars.Load(k)
+ f(KeyValue{k, val.(Var)})
+ }
+}
+
+func expvarHandler(w http.ResponseWriter, r *http.Request) {
+ w.Header().Set("Content-Type", "application/json; charset=utf-8")
+ fmt.Fprintf(w, "{\n")
+ first := true
+ Do(func(kv KeyValue) {
+ if !first {
+ fmt.Fprintf(w, ",\n")
+ }
+ first = false
+ fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
+ })
+ fmt.Fprintf(w, "\n}\n")
+}
+
+// Handler returns the expvar HTTP Handler.
+//
+// This is only needed to install the handler in a non-standard location.
+func Handler() http.Handler {
+ return http.HandlerFunc(expvarHandler)
+}
+
+func cmdline() interface{} {
+ return os.Args
+}
+
+func memstats() interface{} {
+ stats := new(runtime.MemStats)
+ runtime.ReadMemStats(stats)
+ return *stats
+}
+
+func init() {
+ http.HandleFunc("/debug/vars", expvarHandler)
+ Publish("cmdline", Func(cmdline))
+ Publish("memstats", Func(memstats))
+}
diff --git a/src/expvar/expvar_test.go b/src/expvar/expvar_test.go
new file mode 100644
index 0000000..69b0a76
--- /dev/null
+++ b/src/expvar/expvar_test.go
@@ -0,0 +1,601 @@
+// Copyright 2009 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 expvar
+
+import (
+ "bytes"
+ "crypto/sha1"
+ "encoding/json"
+ "fmt"
+ "net"
+ "net/http/httptest"
+ "reflect"
+ "runtime"
+ "strconv"
+ "sync"
+ "sync/atomic"
+ "testing"
+)
+
+// RemoveAll removes all exported variables.
+// This is for tests only.
+func RemoveAll() {
+ varKeysMu.Lock()
+ defer varKeysMu.Unlock()
+ for _, k := range varKeys {
+ vars.Delete(k)
+ }
+ varKeys = nil
+}
+
+func TestNil(t *testing.T) {
+ RemoveAll()
+ val := Get("missing")
+ if val != nil {
+ t.Errorf("got %v, want nil", val)
+ }
+}
+
+func TestInt(t *testing.T) {
+ RemoveAll()
+ reqs := NewInt("requests")
+ if i := reqs.Value(); i != 0 {
+ t.Errorf("reqs.Value() = %v, want 0", i)
+ }
+ if reqs != Get("requests").(*Int) {
+ t.Errorf("Get() failed.")
+ }
+
+ reqs.Add(1)
+ reqs.Add(3)
+ if i := reqs.Value(); i != 4 {
+ t.Errorf("reqs.Value() = %v, want 4", i)
+ }
+
+ if s := reqs.String(); s != "4" {
+ t.Errorf("reqs.String() = %q, want \"4\"", s)
+ }
+
+ reqs.Set(-2)
+ if i := reqs.Value(); i != -2 {
+ t.Errorf("reqs.Value() = %v, want -2", i)
+ }
+}
+
+func BenchmarkIntAdd(b *testing.B) {
+ var v Int
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ v.Add(1)
+ }
+ })
+}
+
+func BenchmarkIntSet(b *testing.B) {
+ var v Int
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ v.Set(1)
+ }
+ })
+}
+
+func TestFloat(t *testing.T) {
+ RemoveAll()
+ reqs := NewFloat("requests-float")
+ if reqs.f != 0.0 {
+ t.Errorf("reqs.f = %v, want 0", reqs.f)
+ }
+ if reqs != Get("requests-float").(*Float) {
+ t.Errorf("Get() failed.")
+ }
+
+ reqs.Add(1.5)
+ reqs.Add(1.25)
+ if v := reqs.Value(); v != 2.75 {
+ t.Errorf("reqs.Value() = %v, want 2.75", v)
+ }
+
+ if s := reqs.String(); s != "2.75" {
+ t.Errorf("reqs.String() = %q, want \"4.64\"", s)
+ }
+
+ reqs.Add(-2)
+ if v := reqs.Value(); v != 0.75 {
+ t.Errorf("reqs.Value() = %v, want 0.75", v)
+ }
+}
+
+func BenchmarkFloatAdd(b *testing.B) {
+ var f Float
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ f.Add(1.0)
+ }
+ })
+}
+
+func BenchmarkFloatSet(b *testing.B) {
+ var f Float
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ f.Set(1.0)
+ }
+ })
+}
+
+func TestString(t *testing.T) {
+ RemoveAll()
+ name := NewString("my-name")
+ if s := name.Value(); s != "" {
+ t.Errorf(`NewString("my-name").Value() = %q, want ""`, s)
+ }
+
+ name.Set("Mike")
+ if s, want := name.String(), `"Mike"`; s != want {
+ t.Errorf(`after name.Set("Mike"), name.String() = %q, want %q`, s, want)
+ }
+ if s, want := name.Value(), "Mike"; s != want {
+ t.Errorf(`after name.Set("Mike"), name.Value() = %q, want %q`, s, want)
+ }
+
+ // Make sure we produce safe JSON output.
+ name.Set("<")
+ if s, want := name.String(), "\"\\u003c\""; s != want {
+ t.Errorf(`after name.Set("<"), name.String() = %q, want %q`, s, want)
+ }
+}
+
+func BenchmarkStringSet(b *testing.B) {
+ var s String
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ s.Set("red")
+ }
+ })
+}
+
+func TestMapInit(t *testing.T) {
+ RemoveAll()
+ colors := NewMap("bike-shed-colors")
+ colors.Add("red", 1)
+ colors.Add("blue", 1)
+ colors.Add("chartreuse", 1)
+
+ n := 0
+ colors.Do(func(KeyValue) { n++ })
+ if n != 3 {
+ t.Errorf("after three Add calls with distinct keys, Do should invoke f 3 times; got %v", n)
+ }
+
+ colors.Init()
+
+ n = 0
+ colors.Do(func(KeyValue) { n++ })
+ if n != 0 {
+ t.Errorf("after Init, Do should invoke f 0 times; got %v", n)
+ }
+}
+
+func TestMapDelete(t *testing.T) {
+ RemoveAll()
+ colors := NewMap("bike-shed-colors")
+
+ colors.Add("red", 1)
+ colors.Add("red", 2)
+ colors.Add("blue", 4)
+
+ n := 0
+ colors.Do(func(KeyValue) { n++ })
+ if n != 2 {
+ t.Errorf("after two Add calls with distinct keys, Do should invoke f 2 times; got %v", n)
+ }
+
+ colors.Delete("red")
+ n = 0
+ colors.Do(func(KeyValue) { n++ })
+ if n != 1 {
+ t.Errorf("removed red, Do should invoke f 1 times; got %v", n)
+ }
+
+ colors.Delete("notfound")
+ n = 0
+ colors.Do(func(KeyValue) { n++ })
+ if n != 1 {
+ t.Errorf("attempted to remove notfound, Do should invoke f 1 times; got %v", n)
+ }
+
+ colors.Delete("blue")
+ colors.Delete("blue")
+ n = 0
+ colors.Do(func(KeyValue) { n++ })
+ if n != 0 {
+ t.Errorf("all keys removed, Do should invoke f 0 times; got %v", n)
+ }
+}
+
+func TestMapCounter(t *testing.T) {
+ RemoveAll()
+ colors := NewMap("bike-shed-colors")
+
+ colors.Add("red", 1)
+ colors.Add("red", 2)
+ colors.Add("blue", 4)
+ colors.AddFloat(`green "midori"`, 4.125)
+ if x := colors.Get("red").(*Int).Value(); x != 3 {
+ t.Errorf("colors.m[\"red\"] = %v, want 3", x)
+ }
+ if x := colors.Get("blue").(*Int).Value(); x != 4 {
+ t.Errorf("colors.m[\"blue\"] = %v, want 4", x)
+ }
+ if x := colors.Get(`green "midori"`).(*Float).Value(); x != 4.125 {
+ t.Errorf("colors.m[`green \"midori\"] = %v, want 4.125", x)
+ }
+
+ // colors.String() should be '{"red":3, "blue":4}',
+ // though the order of red and blue could vary.
+ s := colors.String()
+ var j interface{}
+ err := json.Unmarshal([]byte(s), &j)
+ if err != nil {
+ t.Errorf("colors.String() isn't valid JSON: %v", err)
+ }
+ m, ok := j.(map[string]interface{})
+ if !ok {
+ t.Error("colors.String() didn't produce a map.")
+ }
+ red := m["red"]
+ x, ok := red.(float64)
+ if !ok {
+ t.Error("red.Kind() is not a number.")
+ }
+ if x != 3 {
+ t.Errorf("red = %v, want 3", x)
+ }
+}
+
+func BenchmarkMapSet(b *testing.B) {
+ m := new(Map).Init()
+
+ v := new(Int)
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ m.Set("red", v)
+ }
+ })
+}
+
+func BenchmarkMapSetDifferent(b *testing.B) {
+ procKeys := make([][]string, runtime.GOMAXPROCS(0))
+ for i := range procKeys {
+ keys := make([]string, 4)
+ for j := range keys {
+ keys[j] = fmt.Sprint(i, j)
+ }
+ procKeys[i] = keys
+ }
+
+ m := new(Map).Init()
+ v := new(Int)
+ b.ResetTimer()
+
+ var n int32
+ b.RunParallel(func(pb *testing.PB) {
+ i := int(atomic.AddInt32(&n, 1)-1) % len(procKeys)
+ keys := procKeys[i]
+
+ for pb.Next() {
+ for _, k := range keys {
+ m.Set(k, v)
+ }
+ }
+ })
+}
+
+// BenchmarkMapSetDifferentRandom simulates such a case where the concerned
+// keys of Map.Set are generated dynamically and as a result insertion is
+// out of order and the number of the keys may be large.
+func BenchmarkMapSetDifferentRandom(b *testing.B) {
+ keys := make([]string, 100)
+ for i := range keys {
+ keys[i] = fmt.Sprintf("%x", sha1.Sum([]byte(fmt.Sprint(i))))
+ }
+
+ v := new(Int)
+ b.ResetTimer()
+
+ for i := 0; i < b.N; i++ {
+ m := new(Map).Init()
+ for _, k := range keys {
+ m.Set(k, v)
+ }
+ }
+}
+
+func BenchmarkMapSetString(b *testing.B) {
+ m := new(Map).Init()
+
+ v := new(String)
+ v.Set("Hello, !")
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ m.Set("red", v)
+ }
+ })
+}
+
+func BenchmarkMapAddSame(b *testing.B) {
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ m := new(Map).Init()
+ m.Add("red", 1)
+ m.Add("red", 1)
+ m.Add("red", 1)
+ m.Add("red", 1)
+ }
+ })
+}
+
+func BenchmarkMapAddDifferent(b *testing.B) {
+ procKeys := make([][]string, runtime.GOMAXPROCS(0))
+ for i := range procKeys {
+ keys := make([]string, 4)
+ for j := range keys {
+ keys[j] = fmt.Sprint(i, j)
+ }
+ procKeys[i] = keys
+ }
+
+ b.ResetTimer()
+
+ var n int32
+ b.RunParallel(func(pb *testing.PB) {
+ i := int(atomic.AddInt32(&n, 1)-1) % len(procKeys)
+ keys := procKeys[i]
+
+ for pb.Next() {
+ m := new(Map).Init()
+ for _, k := range keys {
+ m.Add(k, 1)
+ }
+ }
+ })
+}
+
+// BenchmarkMapAddDifferentRandom simulates such a case where that the concerned
+// keys of Map.Add are generated dynamically and as a result insertion is out of
+// order and the number of the keys may be large.
+func BenchmarkMapAddDifferentRandom(b *testing.B) {
+ keys := make([]string, 100)
+ for i := range keys {
+ keys[i] = fmt.Sprintf("%x", sha1.Sum([]byte(fmt.Sprint(i))))
+ }
+
+ b.ResetTimer()
+
+ for i := 0; i < b.N; i++ {
+ m := new(Map).Init()
+ for _, k := range keys {
+ m.Add(k, 1)
+ }
+ }
+}
+
+func BenchmarkMapAddSameSteadyState(b *testing.B) {
+ m := new(Map).Init()
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ m.Add("red", 1)
+ }
+ })
+}
+
+func BenchmarkMapAddDifferentSteadyState(b *testing.B) {
+ procKeys := make([][]string, runtime.GOMAXPROCS(0))
+ for i := range procKeys {
+ keys := make([]string, 4)
+ for j := range keys {
+ keys[j] = fmt.Sprint(i, j)
+ }
+ procKeys[i] = keys
+ }
+
+ m := new(Map).Init()
+ b.ResetTimer()
+
+ var n int32
+ b.RunParallel(func(pb *testing.PB) {
+ i := int(atomic.AddInt32(&n, 1)-1) % len(procKeys)
+ keys := procKeys[i]
+
+ for pb.Next() {
+ for _, k := range keys {
+ m.Add(k, 1)
+ }
+ }
+ })
+}
+
+func TestFunc(t *testing.T) {
+ RemoveAll()
+ var x interface{} = []string{"a", "b"}
+ f := Func(func() interface{} { return x })
+ if s, exp := f.String(), `["a","b"]`; s != exp {
+ t.Errorf(`f.String() = %q, want %q`, s, exp)
+ }
+ if v := f.Value(); !reflect.DeepEqual(v, x) {
+ t.Errorf(`f.Value() = %q, want %q`, v, x)
+ }
+
+ x = 17
+ if s, exp := f.String(), `17`; s != exp {
+ t.Errorf(`f.String() = %q, want %q`, s, exp)
+ }
+}
+
+func TestHandler(t *testing.T) {
+ RemoveAll()
+ m := NewMap("map1")
+ m.Add("a", 1)
+ m.Add("z", 2)
+ m2 := NewMap("map2")
+ for i := 0; i < 9; i++ {
+ m2.Add(strconv.Itoa(i), int64(i))
+ }
+ rr := httptest.NewRecorder()
+ rr.Body = new(bytes.Buffer)
+ expvarHandler(rr, nil)
+ want := `{
+"map1": {"a": 1, "z": 2},
+"map2": {"0": 0, "1": 1, "2": 2, "3": 3, "4": 4, "5": 5, "6": 6, "7": 7, "8": 8}
+}
+`
+ if got := rr.Body.String(); got != want {
+ t.Errorf("HTTP handler wrote:\n%s\nWant:\n%s", got, want)
+ }
+}
+
+func BenchmarkRealworldExpvarUsage(b *testing.B) {
+ var (
+ bytesSent Int
+ bytesRead Int
+ )
+
+ // The benchmark creates GOMAXPROCS client/server pairs.
+ // Each pair creates 4 goroutines: client reader/writer and server reader/writer.
+ // The benchmark stresses concurrent reading and writing to the same connection.
+ // Such pattern is used in net/http and net/rpc.
+
+ b.StopTimer()
+
+ P := runtime.GOMAXPROCS(0)
+ N := b.N / P
+ W := 1000
+
+ // Setup P client/server connections.
+ clients := make([]net.Conn, P)
+ servers := make([]net.Conn, P)
+ ln, err := net.Listen("tcp", "127.0.0.1:0")
+ if err != nil {
+ b.Fatalf("Listen failed: %v", err)
+ }
+ defer ln.Close()
+ done := make(chan bool, 1)
+ go func() {
+ for p := 0; p < P; p++ {
+ s, err := ln.Accept()
+ if err != nil {
+ b.Errorf("Accept failed: %v", err)
+ done <- false
+ return
+ }
+ servers[p] = s
+ }
+ done <- true
+ }()
+ for p := 0; p < P; p++ {
+ c, err := net.Dial("tcp", ln.Addr().String())
+ if err != nil {
+ <-done
+ b.Fatalf("Dial failed: %v", err)
+ }
+ clients[p] = c
+ }
+ if !<-done {
+ b.FailNow()
+ }
+
+ b.StartTimer()
+
+ var wg sync.WaitGroup
+ wg.Add(4 * P)
+ for p := 0; p < P; p++ {
+ // Client writer.
+ go func(c net.Conn) {
+ defer wg.Done()
+ var buf [1]byte
+ for i := 0; i < N; i++ {
+ v := byte(i)
+ for w := 0; w < W; w++ {
+ v *= v
+ }
+ buf[0] = v
+ n, err := c.Write(buf[:])
+ if err != nil {
+ b.Errorf("Write failed: %v", err)
+ return
+ }
+
+ bytesSent.Add(int64(n))
+ }
+ }(clients[p])
+
+ // Pipe between server reader and server writer.
+ pipe := make(chan byte, 128)
+
+ // Server reader.
+ go func(s net.Conn) {
+ defer wg.Done()
+ var buf [1]byte
+ for i := 0; i < N; i++ {
+ n, err := s.Read(buf[:])
+
+ if err != nil {
+ b.Errorf("Read failed: %v", err)
+ return
+ }
+
+ bytesRead.Add(int64(n))
+ pipe <- buf[0]
+ }
+ }(servers[p])
+
+ // Server writer.
+ go func(s net.Conn) {
+ defer wg.Done()
+ var buf [1]byte
+ for i := 0; i < N; i++ {
+ v := <-pipe
+ for w := 0; w < W; w++ {
+ v *= v
+ }
+ buf[0] = v
+ n, err := s.Write(buf[:])
+ if err != nil {
+ b.Errorf("Write failed: %v", err)
+ return
+ }
+
+ bytesSent.Add(int64(n))
+ }
+ s.Close()
+ }(servers[p])
+
+ // Client reader.
+ go func(c net.Conn) {
+ defer wg.Done()
+ var buf [1]byte
+ for i := 0; i < N; i++ {
+ n, err := c.Read(buf[:])
+
+ if err != nil {
+ b.Errorf("Read failed: %v", err)
+ return
+ }
+
+ bytesRead.Add(int64(n))
+ }
+ c.Close()
+ }(clients[p])
+ }
+ wg.Wait()
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-12 16:29:11 +0000