summaryrefslogtreecommitdiff
path: root/libgo/go/runtime/proc_test.go
blob: 1d20a58a420be06a59fe92ddb9f40ad50ae6f515 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
// 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 (
	"runtime"
	"sync/atomic"
	"testing"
)

var stop = make(chan bool, 1)

func perpetuumMobile() {
	select {
	case <-stop:
	default:
		go perpetuumMobile()
	}
}

func TestStopTheWorldDeadlock(t *testing.T) {
	if testing.Short() {
		t.Logf("skipping during short test")
		return
	}
	maxprocs := runtime.GOMAXPROCS(3)
	compl := make(chan bool, 2)
	go func() {
		for i := 0; i != 1000; i += 1 {
			runtime.GC()
		}
		compl <- true
	}()
	go func() {
		for i := 0; i != 1000; i += 1 {
			runtime.GOMAXPROCS(3)
		}
		compl <- true
	}()
	go perpetuumMobile()
	<-compl
	<-compl
	stop <- true
	runtime.GOMAXPROCS(maxprocs)
}

func stackGrowthRecursive(i int) {
	var pad [128]uint64
	if i != 0 && pad[0] == 0 {
		stackGrowthRecursive(i - 1)
	}
}

func BenchmarkStackGrowth(b *testing.B) {
	const CallsPerSched = 1000
	procs := runtime.GOMAXPROCS(-1)
	N := int32(b.N / CallsPerSched)
	c := make(chan bool, procs)
	for p := 0; p < procs; p++ {
		go func() {
			for atomic.AddInt32(&N, -1) >= 0 {
				runtime.Gosched()
				for g := 0; g < CallsPerSched; g++ {
					stackGrowthRecursive(10)
				}
			}
			c <- true
		}()
	}
	for p := 0; p < procs; p++ {
		<-c
	}
}

/* These benchmarks are meaningless for gccgo.

func BenchmarkSyscall(b *testing.B) {
	const CallsPerSched = 1000
	procs := runtime.GOMAXPROCS(-1)
	N := int32(b.N / CallsPerSched)
	c := make(chan bool, procs)
	for p := 0; p < procs; p++ {
		go func() {
			for atomic.AddInt32(&N, -1) >= 0 {
				runtime.Gosched()
				for g := 0; g < CallsPerSched; g++ {
					runtime.Entersyscall()
					runtime.Exitsyscall()
				}
			}
			c <- true
		}()
	}
	for p := 0; p < procs; p++ {
		<-c
	}
}

func BenchmarkSyscallWork(b *testing.B) {
	const CallsPerSched = 1000
	const LocalWork = 100
	procs := runtime.GOMAXPROCS(-1)
	N := int32(b.N / CallsPerSched)
	c := make(chan bool, procs)
	for p := 0; p < procs; p++ {
		go func() {
			foo := 42
			for atomic.AddInt32(&N, -1) >= 0 {
				runtime.Gosched()
				for g := 0; g < CallsPerSched; g++ {
					runtime.Entersyscall()
					for i := 0; i < LocalWork; i++ {
						foo *= 2
						foo /= 2
					}
					runtime.Exitsyscall()
				}
			}
			c <- foo == 42
		}()
	}
	for p := 0; p < procs; p++ {
		<-c
	}
}

*/