1 package metrics
2
3 import (
4 "runtime"
5 "runtime/debug"
6 "testing"
7 "time"
8 )
9
10 func BenchmarkDebugGCStats(b *testing.B) {
11 r := NewRegistry()
12 RegisterDebugGCStats(r)
13 b.ResetTimer()
14 for i := 0; i < b.N; i++ {
15 CaptureDebugGCStatsOnce(r)
16 }
17 }
18
19 func TestDebugGCStatsBlocking(t *testing.T) {
20 if g := runtime.GOMAXPROCS(0); g < 2 {
21 t.Skipf("skipping TestDebugGCMemStatsBlocking with GOMAXPROCS=%d\n", g)
22 return
23 }
24 ch := make(chan int)
25 go testDebugGCStatsBlocking(ch)
26 var gcStats debug.GCStats
27 t0 := time.Now()
28 debug.ReadGCStats(&gcStats)
29 t1 := time.Now()
30 t.Log("i++ during debug.ReadGCStats:", <-ch)
31 go testDebugGCStatsBlocking(ch)
32 d := t1.Sub(t0)
33 t.Log(d)
34 time.Sleep(d)
35 t.Log("i++ during time.Sleep:", <-ch)
36 }
37
38 func testDebugGCStatsBlocking(ch chan int) {
39 i := 0
40 for {
41 select {
42 case ch <- i:
43 return
44 default:
45 i++
46 }
47 }
48 }
49
50 func TestDebugGCStatsDoubleRegister(t *testing.T) {
51 r := NewRegistry()
52 RegisterDebugGCStats(r)
53 var storedGauge = (r.Get("debug.GCStats.LastGC")).(Gauge)
54
55 runtime.GC()
56 CaptureDebugGCStatsOnce(r)
57
58 firstGC := storedGauge.Value()
59 if 0 == firstGC {
60 t.Errorf("firstGC got %d, expected > 0", firstGC)
61 }
62
63 time.Sleep(time.Millisecond)
64
65 RegisterDebugGCStats(r)
66 runtime.GC()
67 CaptureDebugGCStatsOnce(r)
68 if lastGC := storedGauge.Value(); firstGC == lastGC {
69 t.Errorf("lastGC got %d, expected a higher timestamp value", lastGC)
70 }
71 }
72
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