gcc/testsuite/go.test/test/chan/select2.go

   1 // $G $D/$F.go && $L $F.$A && ./$A.out
   2
   3 // Copyright 2010 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 package main
   8
   9 import "runtime"
  10
  11 func sender(c chan int, n int) {
  12         for i := 0; i < n; i++ {
  13                 c <- 1
  14         }
  15 }
  16
  17 func receiver(c, dummy chan int, n int) {
  18         for i := 0; i < n; i++ {
  19                 select {
  20                 case <-c:
  21                         // nothing
  22                 case <-dummy:
  23                         panic("dummy")
  24                 }
  25         }
  26 }
  27
  28 func main() {
  29         runtime.MemProfileRate = 0
  30
  31         c := make(chan int)
  32         dummy := make(chan int)
  33
  34         // warm up
  35         go sender(c, 100000)
  36         receiver(c, dummy, 100000)
  37         runtime.GC()
  38         runtime.MemStats.Alloc = 0
  39
  40         // second time shouldn't increase footprint by much
  41         go sender(c, 100000)
  42         receiver(c, dummy, 100000)
  43         runtime.GC()
  44
  45         if runtime.MemStats.Alloc > 1e5 {
  46                 println("BUG: too much memory for 100,000 selects:", runtime.MemStats.Alloc)
  47         }
  48 }