File: sleep_test.go

package info (click to toggle)
golang-1.11 1.11.12-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, experimental, sid
  • size: 107,360 kB
  • sloc: asm: 88,993; ansic: 8,174; perl: 2,007; sh: 1,804; xml: 623; python: 346; makefile: 123; cpp: 22; f90: 8; awk: 7
file content (476 lines) | stat: -rw-r--r-- 10,359 bytes parent folder | download | duplicates (8)
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
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
// Copyright 2009 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 time_test

import (
	"errors"
	"fmt"
	"runtime"
	"strings"
	"sync"
	"sync/atomic"
	"testing"
	. "time"
)

// Go runtime uses different Windows timers for time.Now and sleeping.
// These can tick at different frequencies and can arrive out of sync.
// The effect can be seen, for example, as time.Sleep(100ms) is actually
// shorter then 100ms when measured as difference between time.Now before and
// after time.Sleep call. This was observed on Windows XP SP3 (windows/386).
// windowsInaccuracy is to ignore such errors.
const windowsInaccuracy = 17 * Millisecond

func TestSleep(t *testing.T) {
	const delay = 100 * Millisecond
	go func() {
		Sleep(delay / 2)
		Interrupt()
	}()
	start := Now()
	Sleep(delay)
	delayadj := delay
	if runtime.GOOS == "windows" {
		delayadj -= windowsInaccuracy
	}
	duration := Now().Sub(start)
	if duration < delayadj {
		t.Fatalf("Sleep(%s) slept for only %s", delay, duration)
	}
}

// Test the basic function calling behavior. Correct queueing
// behavior is tested elsewhere, since After and AfterFunc share
// the same code.
func TestAfterFunc(t *testing.T) {
	i := 10
	c := make(chan bool)
	var f func()
	f = func() {
		i--
		if i >= 0 {
			AfterFunc(0, f)
			Sleep(1 * Second)
		} else {
			c <- true
		}
	}

	AfterFunc(0, f)
	<-c
}

func TestAfterStress(t *testing.T) {
	stop := uint32(0)
	go func() {
		for atomic.LoadUint32(&stop) == 0 {
			runtime.GC()
			// Yield so that the OS can wake up the timer thread,
			// so that it can generate channel sends for the main goroutine,
			// which will eventually set stop = 1 for us.
			Sleep(Nanosecond)
		}
	}()
	ticker := NewTicker(1)
	for i := 0; i < 100; i++ {
		<-ticker.C
	}
	ticker.Stop()
	atomic.StoreUint32(&stop, 1)
}

func benchmark(b *testing.B, bench func(n int)) {

	// Create equal number of garbage timers on each P before starting
	// the benchmark.
	var wg sync.WaitGroup
	garbageAll := make([][]*Timer, runtime.GOMAXPROCS(0))
	for i := range garbageAll {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			garbage := make([]*Timer, 1<<15)
			for j := range garbage {
				garbage[j] = AfterFunc(Hour, nil)
			}
			garbageAll[i] = garbage
		}(i)
	}
	wg.Wait()

	b.ResetTimer()
	b.RunParallel(func(pb *testing.PB) {
		for pb.Next() {
			bench(1000)
		}
	})
	b.StopTimer()

	for _, garbage := range garbageAll {
		for _, t := range garbage {
			t.Stop()
		}
	}
}

func BenchmarkAfterFunc(b *testing.B) {
	benchmark(b, func(n int) {
		c := make(chan bool)
		var f func()
		f = func() {
			n--
			if n >= 0 {
				AfterFunc(0, f)
			} else {
				c <- true
			}
		}

		AfterFunc(0, f)
		<-c
	})
}

func BenchmarkAfter(b *testing.B) {
	benchmark(b, func(n int) {
		for i := 0; i < n; i++ {
			<-After(1)
		}
	})
}

func BenchmarkStop(b *testing.B) {
	benchmark(b, func(n int) {
		for i := 0; i < n; i++ {
			NewTimer(1 * Second).Stop()
		}
	})
}

func BenchmarkSimultaneousAfterFunc(b *testing.B) {
	benchmark(b, func(n int) {
		var wg sync.WaitGroup
		wg.Add(n)
		for i := 0; i < n; i++ {
			AfterFunc(0, wg.Done)
		}
		wg.Wait()
	})
}

func BenchmarkStartStop(b *testing.B) {
	benchmark(b, func(n int) {
		timers := make([]*Timer, n)
		for i := 0; i < n; i++ {
			timers[i] = AfterFunc(Hour, nil)
		}

		for i := 0; i < n; i++ {
			timers[i].Stop()
		}
	})
}

func BenchmarkReset(b *testing.B) {
	benchmark(b, func(n int) {
		t := NewTimer(Hour)
		for i := 0; i < n; i++ {
			t.Reset(Hour)
		}
		t.Stop()
	})
}

func BenchmarkSleep(b *testing.B) {
	benchmark(b, func(n int) {
		var wg sync.WaitGroup
		wg.Add(n)
		for i := 0; i < n; i++ {
			go func() {
				Sleep(Nanosecond)
				wg.Done()
			}()
		}
		wg.Wait()
	})
}

func TestAfter(t *testing.T) {
	const delay = 100 * Millisecond
	start := Now()
	end := <-After(delay)
	delayadj := delay
	if runtime.GOOS == "windows" {
		delayadj -= windowsInaccuracy
	}
	if duration := Now().Sub(start); duration < delayadj {
		t.Fatalf("After(%s) slept for only %d ns", delay, duration)
	}
	if min := start.Add(delayadj); end.Before(min) {
		t.Fatalf("After(%s) expect >= %s, got %s", delay, min, end)
	}
}

func TestAfterTick(t *testing.T) {
	const Count = 10
	Delta := 100 * Millisecond
	if testing.Short() {
		Delta = 10 * Millisecond
	}
	t0 := Now()
	for i := 0; i < Count; i++ {
		<-After(Delta)
	}
	t1 := Now()
	d := t1.Sub(t0)
	target := Delta * Count
	if d < target*9/10 {
		t.Fatalf("%d ticks of %s too fast: took %s, expected %s", Count, Delta, d, target)
	}
	if !testing.Short() && d > target*30/10 {
		t.Fatalf("%d ticks of %s too slow: took %s, expected %s", Count, Delta, d, target)
	}
}

func TestAfterStop(t *testing.T) {
	AfterFunc(100*Millisecond, func() {})
	t0 := NewTimer(50 * Millisecond)
	c1 := make(chan bool, 1)
	t1 := AfterFunc(150*Millisecond, func() { c1 <- true })
	c2 := After(200 * Millisecond)
	if !t0.Stop() {
		t.Fatalf("failed to stop event 0")
	}
	if !t1.Stop() {
		t.Fatalf("failed to stop event 1")
	}
	<-c2
	select {
	case <-t0.C:
		t.Fatalf("event 0 was not stopped")
	case <-c1:
		t.Fatalf("event 1 was not stopped")
	default:
	}
	if t1.Stop() {
		t.Fatalf("Stop returned true twice")
	}
}

func TestAfterQueuing(t *testing.T) {
	// This test flakes out on some systems,
	// so we'll try it a few times before declaring it a failure.
	const attempts = 5
	err := errors.New("!=nil")
	for i := 0; i < attempts && err != nil; i++ {
		delta := Duration(20+i*50) * Millisecond
		if err = testAfterQueuing(delta); err != nil {
			t.Logf("attempt %v failed: %v", i, err)
		}
	}
	if err != nil {
		t.Fatal(err)
	}
}

var slots = []int{5, 3, 6, 6, 6, 1, 1, 2, 7, 9, 4, 8, 0}

type afterResult struct {
	slot int
	t    Time
}

func await(slot int, result chan<- afterResult, ac <-chan Time) {
	result <- afterResult{slot, <-ac}
}

func testAfterQueuing(delta Duration) error {
	// make the result channel buffered because we don't want
	// to depend on channel queueing semantics that might
	// possibly change in the future.
	result := make(chan afterResult, len(slots))

	t0 := Now()
	for _, slot := range slots {
		go await(slot, result, After(Duration(slot)*delta))
	}
	var order []int
	var times []Time
	for range slots {
		r := <-result
		order = append(order, r.slot)
		times = append(times, r.t)
	}
	for i := range order {
		if i > 0 && order[i] < order[i-1] {
			return fmt.Errorf("After calls returned out of order: %v", order)
		}
	}
	for i, t := range times {
		dt := t.Sub(t0)
		target := Duration(order[i]) * delta
		if dt < target-delta/2 || dt > target+delta*10 {
			return fmt.Errorf("After(%s) arrived at %s, expected [%s,%s]", target, dt, target-delta/2, target+delta*10)
		}
	}
	return nil
}

func TestTimerStopStress(t *testing.T) {
	if testing.Short() {
		return
	}
	for i := 0; i < 100; i++ {
		go func(i int) {
			timer := AfterFunc(2*Second, func() {
				t.Fatalf("timer %d was not stopped", i)
			})
			Sleep(1 * Second)
			timer.Stop()
		}(i)
	}
	Sleep(3 * Second)
}

func TestSleepZeroDeadlock(t *testing.T) {
	// Sleep(0) used to hang, the sequence of events was as follows.
	// Sleep(0) sets G's status to Gwaiting, but then immediately returns leaving the status.
	// Then the goroutine calls e.g. new and falls down into the scheduler due to pending GC.
	// After the GC nobody wakes up the goroutine from Gwaiting status.
	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(4))
	c := make(chan bool)
	go func() {
		for i := 0; i < 100; i++ {
			runtime.GC()
		}
		c <- true
	}()
	for i := 0; i < 100; i++ {
		Sleep(0)
		tmp := make(chan bool, 1)
		tmp <- true
		<-tmp
	}
	<-c
}

func testReset(d Duration) error {
	t0 := NewTimer(2 * d)
	Sleep(d)
	if !t0.Reset(3 * d) {
		return errors.New("resetting unfired timer returned false")
	}
	Sleep(2 * d)
	select {
	case <-t0.C:
		return errors.New("timer fired early")
	default:
	}
	Sleep(2 * d)
	select {
	case <-t0.C:
	default:
		return errors.New("reset timer did not fire")
	}

	if t0.Reset(50 * Millisecond) {
		return errors.New("resetting expired timer returned true")
	}
	return nil
}

func TestReset(t *testing.T) {
	// We try to run this test with increasingly larger multiples
	// until one works so slow, loaded hardware isn't as flaky,
	// but without slowing down fast machines unnecessarily.
	const unit = 25 * Millisecond
	tries := []Duration{
		1 * unit,
		3 * unit,
		7 * unit,
		15 * unit,
	}
	var err error
	for _, d := range tries {
		err = testReset(d)
		if err == nil {
			t.Logf("passed using duration %v", d)
			return
		}
	}
	t.Error(err)
}

// Test that sleeping for an interval so large it overflows does not
// result in a short sleep duration.
func TestOverflowSleep(t *testing.T) {
	const big = Duration(int64(1<<63 - 1))
	select {
	case <-After(big):
		t.Fatalf("big timeout fired")
	case <-After(25 * Millisecond):
		// OK
	}
	const neg = Duration(-1 << 63)
	select {
	case <-After(neg):
		// OK
	case <-After(1 * Second):
		t.Fatalf("negative timeout didn't fire")
	}
}

// Test that a panic while deleting a timer does not leave
// the timers mutex held, deadlocking a ticker.Stop in a defer.
func TestIssue5745(t *testing.T) {
	if runtime.GOOS == "darwin" && runtime.GOARCH == "arm" {
		t.Skipf("skipping on %s/%s, see issue 10043", runtime.GOOS, runtime.GOARCH)
	}

	ticker := NewTicker(Hour)
	defer func() {
		// would deadlock here before the fix due to
		// lock taken before the segfault.
		ticker.Stop()

		if r := recover(); r == nil {
			t.Error("Expected panic, but none happened.")
		}
	}()

	// cause a panic due to a segfault
	var timer *Timer
	timer.Stop()
	t.Error("Should be unreachable.")
}

func TestOverflowRuntimeTimer(t *testing.T) {
	if testing.Short() {
		t.Skip("skipping in short mode, see issue 6874")
	}
	// This may hang forever if timers are broken. See comment near
	// the end of CheckRuntimeTimerOverflow in internal_test.go.
	CheckRuntimeTimerOverflow()
}

func checkZeroPanicString(t *testing.T) {
	e := recover()
	s, _ := e.(string)
	if want := "called on uninitialized Timer"; !strings.Contains(s, want) {
		t.Errorf("panic = %v; want substring %q", e, want)
	}
}

func TestZeroTimerResetPanics(t *testing.T) {
	defer checkZeroPanicString(t)
	var tr Timer
	tr.Reset(1)
}

func TestZeroTimerStopPanics(t *testing.T) {
	defer checkZeroPanicString(t)
	var tr Timer
	tr.Stop()
}