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// Copyright 2011 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 (
"os"
"runtime"
"runtime/debug"
"testing"
)
func TestGcSys(t *testing.T) {
if os.Getenv("GOGC") == "off" {
t.Skip("skipping test; GOGC=off in environment")
}
data := struct{ Short bool }{testing.Short()}
got := executeTest(t, testGCSysSource, &data)
want := "OK\n"
if got != want {
t.Fatalf("expected %q, but got %q", want, got)
}
}
const testGCSysSource = `
package main
import (
"fmt"
"runtime"
)
func main() {
runtime.GOMAXPROCS(1)
memstats := new(runtime.MemStats)
runtime.GC()
runtime.ReadMemStats(memstats)
sys := memstats.Sys
runtime.MemProfileRate = 0 // disable profiler
itercount := 1000000
{{if .Short}}
itercount = 100000
{{end}}
for i := 0; i < itercount; i++ {
workthegc()
}
// Should only be using a few MB.
// We allocated 100 MB or (if not short) 1 GB.
runtime.ReadMemStats(memstats)
if sys > memstats.Sys {
sys = 0
} else {
sys = memstats.Sys - sys
}
if sys > 16<<20 {
fmt.Printf("using too much memory: %d bytes\n", sys)
return
}
fmt.Printf("OK\n")
}
func workthegc() []byte {
return make([]byte, 1029)
}
`
func TestGcDeepNesting(t *testing.T) {
type T [2][2][2][2][2][2][2][2][2][2]*int
a := new(T)
// Prevent the compiler from applying escape analysis.
// This makes sure new(T) is allocated on heap, not on the stack.
t.Logf("%p", a)
a[0][0][0][0][0][0][0][0][0][0] = new(int)
*a[0][0][0][0][0][0][0][0][0][0] = 13
runtime.GC()
if *a[0][0][0][0][0][0][0][0][0][0] != 13 {
t.Fail()
}
}
func TestGcHashmapIndirection(t *testing.T) {
defer debug.SetGCPercent(debug.SetGCPercent(1))
runtime.GC()
type T struct {
a [256]int
}
m := make(map[T]T)
for i := 0; i < 2000; i++ {
var a T
a.a[0] = i
m[a] = T{}
}
}
func TestGcArraySlice(t *testing.T) {
type X struct {
buf [1]byte
nextbuf []byte
next *X
}
var head *X
for i := 0; i < 10; i++ {
p := &X{}
p.buf[0] = 42
p.next = head
if head != nil {
p.nextbuf = head.buf[:]
}
head = p
runtime.GC()
}
for p := head; p != nil; p = p.next {
if p.buf[0] != 42 {
t.Fatal("corrupted heap")
}
}
}
func TestGcRescan(t *testing.T) {
type X struct {
c chan error
nextx *X
}
type Y struct {
X
nexty *Y
p *int
}
var head *Y
for i := 0; i < 10; i++ {
p := &Y{}
p.c = make(chan error)
if head != nil {
p.nextx = &head.X
}
p.nexty = head
p.p = new(int)
*p.p = 42
head = p
runtime.GC()
}
for p := head; p != nil; p = p.nexty {
if *p.p != 42 {
t.Fatal("corrupted heap")
}
}
}
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