gcc/testsuite/go.test/test/gc2.go

   1 // run
   2
   3 // Copyright 2011 The Go Authors.  All rights reserved.
   4 // Use of this source code is governed by a BSD-style
   5 // license that can be found in the LICENSE file.
   6
   7 // Test that buffered channels are garbage collected properly.
   8 // An interesting case because they have finalizers and used to
   9 // have self loops that kept them from being collected.
  10 // (Cyclic data with finalizers is never finalized, nor collected.)
  11
  12 package main
  13
  14 import (
  15         "fmt"
  16         "os"
  17         "runtime"
  18 )
  19
  20 func main() {
  21         const N = 10000
  22         st := new(runtime.MemStats)
  23         memstats := new(runtime.MemStats)
  24         runtime.ReadMemStats(st)
  25         for i := 0; i < N; i++ {
  26                 c := make(chan int, 10)
  27                 _ = c
  28                 if i%100 == 0 {
  29                         for j := 0; j < 4; j++ {
  30                                 runtime.GC()
  31                                 runtime.Gosched()
  32                                 runtime.GC()
  33                                 runtime.Gosched()
  34                         }
  35                 }
  36         }
  37
  38         runtime.ReadMemStats(memstats)
  39         obj := memstats.HeapObjects - st.HeapObjects
  40         if obj > N/5 {
  41                 fmt.Println("too many objects left:", obj)
  42                 os.Exit(1)
  43         }
  44 }