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// 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 runtime_test
import (
"flag"
"fmt"
"reflect"
. "runtime"
"testing"
"time"
"unsafe"
)
func TestMemStats(t *testing.T) {
// Make sure there's at least one forced GC.
GC()
// Test that MemStats has sane values.
st := new(MemStats)
ReadMemStats(st)
nz := func(x interface{}) error {
if x != reflect.Zero(reflect.TypeOf(x)).Interface() {
return nil
}
return fmt.Errorf("zero value")
}
le := func(thresh float64) func(interface{}) error {
return func(x interface{}) error {
if reflect.ValueOf(x).Convert(reflect.TypeOf(thresh)).Float() < thresh {
return nil
}
return fmt.Errorf("insanely high value (overflow?); want <= %v", thresh)
}
}
eq := func(x interface{}) func(interface{}) error {
return func(y interface{}) error {
if x == y {
return nil
}
return fmt.Errorf("want %v", x)
}
}
// Of the uint fields, HeapReleased, HeapIdle can be 0.
// PauseTotalNs can be 0 if timer resolution is poor.
fields := map[string][]func(interface{}) error{
"Alloc": {nz, le(1e10)}, "TotalAlloc": {nz, le(1e11)}, "Sys": {nz, le(1e10)},
"Lookups": {nz, le(1e10)}, "Mallocs": {nz, le(1e10)}, "Frees": {nz, le(1e10)},
"HeapAlloc": {nz, le(1e10)}, "HeapSys": {nz, le(1e10)}, "HeapIdle": {le(1e10)},
"HeapInuse": {nz, le(1e10)}, "HeapReleased": {le(1e10)}, "HeapObjects": {nz, le(1e10)},
"StackInuse": {nz, le(1e10)}, "StackSys": {nz, le(1e10)},
"MSpanInuse": {nz, le(1e10)}, "MSpanSys": {nz, le(1e10)},
"MCacheInuse": {nz, le(1e10)}, "MCacheSys": {nz, le(1e10)},
"BuckHashSys": {nz, le(1e10)}, "GCSys": {nz, le(1e10)}, "OtherSys": {nz, le(1e10)},
"NextGC": {nz, le(1e10)}, "LastGC": {nz},
"PauseTotalNs": {le(1e11)}, "PauseNs": nil, "PauseEnd": nil,
"NumGC": {nz, le(1e9)}, "NumForcedGC": {nz, le(1e9)},
"GCCPUFraction": {le(0.99)}, "EnableGC": {eq(true)}, "DebugGC": {eq(false)},
"BySize": nil,
}
rst := reflect.ValueOf(st).Elem()
for i := 0; i < rst.Type().NumField(); i++ {
name, val := rst.Type().Field(i).Name, rst.Field(i).Interface()
checks, ok := fields[name]
if !ok {
t.Errorf("unknown MemStats field %s", name)
continue
}
for _, check := range checks {
if err := check(val); err != nil {
t.Errorf("%s = %v: %s", name, val, err)
}
}
}
if st.Sys != st.HeapSys+st.StackSys+st.MSpanSys+st.MCacheSys+
st.BuckHashSys+st.GCSys+st.OtherSys {
t.Fatalf("Bad sys value: %+v", *st)
}
if st.HeapIdle+st.HeapInuse != st.HeapSys {
t.Fatalf("HeapIdle(%d) + HeapInuse(%d) should be equal to HeapSys(%d), but isn't.", st.HeapIdle, st.HeapInuse, st.HeapSys)
}
if lpe := st.PauseEnd[int(st.NumGC+255)%len(st.PauseEnd)]; st.LastGC != lpe {
t.Fatalf("LastGC(%d) != last PauseEnd(%d)", st.LastGC, lpe)
}
var pauseTotal uint64
for _, pause := range st.PauseNs {
pauseTotal += pause
}
if int(st.NumGC) < len(st.PauseNs) {
// We have all pauses, so this should be exact.
if st.PauseTotalNs != pauseTotal {
t.Fatalf("PauseTotalNs(%d) != sum PauseNs(%d)", st.PauseTotalNs, pauseTotal)
}
for i := int(st.NumGC); i < len(st.PauseNs); i++ {
if st.PauseNs[i] != 0 {
t.Fatalf("Non-zero PauseNs[%d]: %+v", i, st)
}
if st.PauseEnd[i] != 0 {
t.Fatalf("Non-zero PauseEnd[%d]: %+v", i, st)
}
}
} else {
if st.PauseTotalNs < pauseTotal {
t.Fatalf("PauseTotalNs(%d) < sum PauseNs(%d)", st.PauseTotalNs, pauseTotal)
}
}
if st.NumForcedGC > st.NumGC {
t.Fatalf("NumForcedGC(%d) > NumGC(%d)", st.NumForcedGC, st.NumGC)
}
}
func TestStringConcatenationAllocs(t *testing.T) {
n := testing.AllocsPerRun(1e3, func() {
b := make([]byte, 10)
for i := 0; i < 10; i++ {
b[i] = byte(i) + '0'
}
s := "foo" + string(b)
if want := "foo0123456789"; s != want {
t.Fatalf("want %v, got %v", want, s)
}
})
// Only string concatenation allocates.
if n != 1 {
t.Fatalf("want 1 allocation, got %v", n)
}
}
func TestTinyAlloc(t *testing.T) {
const N = 16
var v [N]unsafe.Pointer
for i := range v {
v[i] = unsafe.Pointer(new(byte))
}
chunks := make(map[uintptr]bool, N)
for _, p := range v {
chunks[uintptr(p)&^7] = true
}
if len(chunks) == N {
t.Fatal("no bytes allocated within the same 8-byte chunk")
}
}
var mallocSink uintptr
func BenchmarkMalloc8(b *testing.B) {
var x uintptr
for i := 0; i < b.N; i++ {
p := new(int64)
x ^= uintptr(unsafe.Pointer(p))
}
mallocSink = x
}
func BenchmarkMalloc16(b *testing.B) {
var x uintptr
for i := 0; i < b.N; i++ {
p := new([2]int64)
x ^= uintptr(unsafe.Pointer(p))
}
mallocSink = x
}
func BenchmarkMallocTypeInfo8(b *testing.B) {
var x uintptr
for i := 0; i < b.N; i++ {
p := new(struct {
p [8 / unsafe.Sizeof(uintptr(0))]*int
})
x ^= uintptr(unsafe.Pointer(p))
}
mallocSink = x
}
func BenchmarkMallocTypeInfo16(b *testing.B) {
var x uintptr
for i := 0; i < b.N; i++ {
p := new(struct {
p [16 / unsafe.Sizeof(uintptr(0))]*int
})
x ^= uintptr(unsafe.Pointer(p))
}
mallocSink = x
}
type LargeStruct struct {
x [16][]byte
}
func BenchmarkMallocLargeStruct(b *testing.B) {
var x uintptr
for i := 0; i < b.N; i++ {
p := make([]LargeStruct, 2)
x ^= uintptr(unsafe.Pointer(&p[0]))
}
mallocSink = x
}
var n = flag.Int("n", 1000, "number of goroutines")
func BenchmarkGoroutineSelect(b *testing.B) {
quit := make(chan struct{})
read := func(ch chan struct{}) {
for {
select {
case _, ok := <-ch:
if !ok {
return
}
case <-quit:
return
}
}
}
benchHelper(b, *n, read)
}
func BenchmarkGoroutineBlocking(b *testing.B) {
read := func(ch chan struct{}) {
for {
if _, ok := <-ch; !ok {
return
}
}
}
benchHelper(b, *n, read)
}
func BenchmarkGoroutineForRange(b *testing.B) {
read := func(ch chan struct{}) {
for range ch {
}
}
benchHelper(b, *n, read)
}
func benchHelper(b *testing.B, n int, read func(chan struct{})) {
m := make([]chan struct{}, n)
for i := range m {
m[i] = make(chan struct{}, 1)
go read(m[i])
}
b.StopTimer()
b.ResetTimer()
GC()
for i := 0; i < b.N; i++ {
for _, ch := range m {
if ch != nil {
ch <- struct{}{}
}
}
time.Sleep(10 * time.Millisecond)
b.StartTimer()
GC()
b.StopTimer()
}
for _, ch := range m {
close(ch)
}
time.Sleep(10 * time.Millisecond)
}
func BenchmarkGoroutineIdle(b *testing.B) {
quit := make(chan struct{})
fn := func() {
<-quit
}
for i := 0; i < *n; i++ {
go fn()
}
GC()
b.ResetTimer()
for i := 0; i < b.N; i++ {
GC()
}
b.StopTimer()
close(quit)
time.Sleep(10 * time.Millisecond)
}