-
Notifications
You must be signed in to change notification settings - Fork 400
/
sample_and_watermark.go
209 lines (182 loc) · 7.55 KB
/
sample_and_watermark.go
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
/*
Copyright 2019 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package metrics
import (
"sync"
"time"
compbasemetrics "k8s.io/component-base/metrics"
"k8s.io/klog/v2"
"k8s.io/utils/clock"
)
const (
labelNameMark = "mark"
labelValueLo = "low"
labelValueHi = "high"
labelNamePhase = "phase"
labelValueWaiting = "waiting"
labelValueExecuting = "executing"
)
// SampleAndWaterMarkPairGenerator makes pairs of RatioedChangeObservers that
// track samples and watermarks.
type SampleAndWaterMarkPairGenerator struct {
urGenerator SampleAndWaterMarkObserverGenerator
}
var _ RatioedChangeObserverPairGenerator = SampleAndWaterMarkPairGenerator{}
// NewSampleAndWaterMarkHistogramsPairGenerator makes a new pair generator
func NewSampleAndWaterMarkHistogramsPairGenerator(clock clock.PassiveClock, samplePeriod time.Duration, sampleOpts, waterMarkOpts *compbasemetrics.HistogramOpts, labelNames []string) SampleAndWaterMarkPairGenerator {
return SampleAndWaterMarkPairGenerator{
urGenerator: NewSampleAndWaterMarkHistogramsGenerator(clock, samplePeriod, sampleOpts, waterMarkOpts, append([]string{labelNamePhase}, labelNames...)),
}
}
// Generate makes a new pair
func (spg SampleAndWaterMarkPairGenerator) Generate(initialWaitingDenominator, initialExecutingDenominator float64, labelValues []string) RatioedChangeObserverPair {
return RatioedChangeObserverPair{
RequestsWaiting: spg.urGenerator.Generate(0, initialWaitingDenominator, append([]string{labelValueWaiting}, labelValues...)),
RequestsExecuting: spg.urGenerator.Generate(0, initialExecutingDenominator, append([]string{labelValueExecuting}, labelValues...)),
}
}
func (spg SampleAndWaterMarkPairGenerator) metrics() Registerables {
return spg.urGenerator.metrics()
}
// SampleAndWaterMarkObserverGenerator creates RatioedChangeObservers that
// populate histograms of samples and low- and high-water-marks. The
// generator has a samplePeriod, and the histograms get an observation
// every samplePeriod. The sampling windows are quantized based on
// the monotonic rather than wall-clock times. The `t0` field is
// there so to provide a baseline for monotonic clock differences.
type SampleAndWaterMarkObserverGenerator struct {
*sampleAndWaterMarkObserverGenerator
}
type sampleAndWaterMarkObserverGenerator struct {
clock clock.PassiveClock
t0 time.Time
samplePeriod time.Duration
samples *compbasemetrics.HistogramVec
waterMarks *compbasemetrics.HistogramVec
}
var _ RatioedChangeObserverGenerator = SampleAndWaterMarkObserverGenerator{}
// NewSampleAndWaterMarkHistogramsGenerator makes a new one
func NewSampleAndWaterMarkHistogramsGenerator(clock clock.PassiveClock, samplePeriod time.Duration, sampleOpts, waterMarkOpts *compbasemetrics.HistogramOpts, labelNames []string) SampleAndWaterMarkObserverGenerator {
return SampleAndWaterMarkObserverGenerator{
&sampleAndWaterMarkObserverGenerator{
clock: clock,
t0: clock.Now(),
samplePeriod: samplePeriod,
samples: compbasemetrics.NewHistogramVec(sampleOpts, labelNames),
waterMarks: compbasemetrics.NewHistogramVec(waterMarkOpts, append([]string{labelNameMark}, labelNames...)),
}}
}
func (swg *sampleAndWaterMarkObserverGenerator) quantize(when time.Time) int64 {
return int64(when.Sub(swg.t0) / swg.samplePeriod)
}
// Generate makes a new RatioedChangeObserver
func (swg *sampleAndWaterMarkObserverGenerator) Generate(initialNumerator, initialDenominator float64, labelValues []string) RatioedChangeObserver {
ratio := initialNumerator / initialDenominator
when := swg.clock.Now()
return &sampleAndWaterMarkHistograms{
sampleAndWaterMarkObserverGenerator: swg,
labelValues: labelValues,
loLabelValues: append([]string{labelValueLo}, labelValues...),
hiLabelValues: append([]string{labelValueHi}, labelValues...),
denominator: initialDenominator,
sampleAndWaterMarkAccumulator: sampleAndWaterMarkAccumulator{
lastSet: when,
lastSetInt: swg.quantize(when),
numerator: initialNumerator,
ratio: ratio,
loRatio: ratio,
hiRatio: ratio,
}}
}
func (swg *sampleAndWaterMarkObserverGenerator) metrics() Registerables {
return Registerables{swg.samples, swg.waterMarks}
}
type sampleAndWaterMarkHistograms struct {
*sampleAndWaterMarkObserverGenerator
labelValues []string
loLabelValues, hiLabelValues []string
sync.Mutex
denominator float64
sampleAndWaterMarkAccumulator
}
type sampleAndWaterMarkAccumulator struct {
lastSet time.Time
lastSetInt int64 // lastSet / samplePeriod
numerator float64
ratio float64 // numerator/denominator
loRatio, hiRatio float64
}
var _ RatioedChangeObserver = (*sampleAndWaterMarkHistograms)(nil)
func (saw *sampleAndWaterMarkHistograms) Add(deltaNumerator float64) {
saw.innerSet(func() {
saw.numerator += deltaNumerator
})
}
func (saw *sampleAndWaterMarkHistograms) Observe(numerator float64) {
saw.innerSet(func() {
saw.numerator = numerator
})
}
func (saw *sampleAndWaterMarkHistograms) SetDenominator(denominator float64) {
saw.innerSet(func() {
saw.denominator = denominator
})
}
func (saw *sampleAndWaterMarkHistograms) innerSet(updateNumeratorOrDenominator func()) {
when, whenInt, acc, wellOrdered := func() (time.Time, int64, sampleAndWaterMarkAccumulator, bool) {
saw.Lock()
defer saw.Unlock()
// Moved these variables here to tiptoe around https://github.com/golang/go/issues/43570 for #97685
when := saw.clock.Now()
whenInt := saw.quantize(when)
acc := saw.sampleAndWaterMarkAccumulator
wellOrdered := !when.Before(acc.lastSet)
updateNumeratorOrDenominator()
saw.ratio = saw.numerator / saw.denominator
if wellOrdered {
if acc.lastSetInt < whenInt {
saw.loRatio, saw.hiRatio = acc.ratio, acc.ratio
saw.lastSetInt = whenInt
}
saw.lastSet = when
}
// `wellOrdered` should always be true because we are using
// monotonic clock readings and they never go backwards. Yet
// very small backwards steps (under 1 microsecond) have been
// observed
// (https://github.com/kubernetes/kubernetes/issues/96459).
// In the backwards case, treat the current reading as if it
// had occurred at time `saw.lastSet` and log an error. It
// would be wrong to update `saw.lastSet` in this case because
// that plants a time bomb for future updates to
// `saw.lastSetInt`.
if saw.ratio < saw.loRatio {
saw.loRatio = saw.ratio
} else if saw.ratio > saw.hiRatio {
saw.hiRatio = saw.ratio
}
return when, whenInt, acc, wellOrdered
}()
if !wellOrdered {
lastSetS := acc.lastSet.String()
whenS := when.String()
klog.Errorf("Time went backwards from %s to %s for labelValues=%#+v", lastSetS, whenS, saw.labelValues)
}
for acc.lastSetInt < whenInt {
saw.samples.WithLabelValues(saw.labelValues...).Observe(acc.ratio)
saw.waterMarks.WithLabelValues(saw.loLabelValues...).Observe(acc.loRatio)
saw.waterMarks.WithLabelValues(saw.hiLabelValues...).Observe(acc.hiRatio)
acc.lastSetInt++
acc.loRatio, acc.hiRatio = acc.ratio, acc.ratio
}
}