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Merge pull request #221 from stevvooe/benchmark-with-labels-metric-vec 

metricvec: handle hash collision for labeled metrics
This commit is contained in:
Björn Rabenstein 2016-08-17 09:36:54 +02:00 committed by GitHub
parent 25db044749 4db77b04a8
commit dadfef856f
7 changed files with 364 additions and 101 deletions
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8
prometheus/counter.go
View File

@ -96,10 +96,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
opts.ConstLabels,
)
return &CounterVec{
MetricVec: MetricVec{
children: map[uint64]Metric{},
desc: desc,
newMetric: func(lvs ...string) Metric {
MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
result := &counter{value: value{
desc: desc,
valType: CounterValue,
@ -107,8 +104,7 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
}}
result.init(result) // Init self-collection.
return result
},
},
}),
}
}

8
prometheus/gauge.go
View File

@ -72,13 +72,9 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
opts.ConstLabels,
)
return &GaugeVec{
MetricVec: MetricVec{
children: map[uint64]Metric{},
desc: desc,
newMetric: func(lvs ...string) Metric {
MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
return newValue(desc, GaugeValue, 0, lvs...)
},
},
}),
}
}

8
prometheus/histogram.go
View File

@ -301,13 +301,9 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
opts.ConstLabels,
)
return &HistogramVec{
MetricVec: MetricVec{
children: map[uint64]Metric{},
desc: desc,
newMetric: func(lvs ...string) Metric {
MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
return newHistogram(desc, opts, lvs...)
},
},
}),
}
}

8
prometheus/summary.go
View File

@ -404,13 +404,9 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
opts.ConstLabels,
)
return &SummaryVec{
MetricVec: MetricVec{
children: map[uint64]Metric{},
desc: desc,
newMetric: func(lvs ...string) Metric {
MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
return newSummary(desc, opts, lvs...)
},
},
}),
}
}

8
prometheus/untyped.go
View File

@ -70,13 +70,9 @@ func NewUntypedVec(opts UntypedOpts, labelNames []string) *UntypedVec {
opts.ConstLabels,
)
return &UntypedVec{
MetricVec: MetricVec{
children: map[uint64]Metric{},
desc: desc,
newMetric: func(lvs ...string) Metric {
MetricVec: newMetricVec(desc, func(lvs ...string) Metric {
return newValue(desc, UntypedValue, 0, lvs...)
},
},
}),
}
}

211
prometheus/vec.go
View File

@ -16,6 +16,8 @@ package prometheus
import (
"fmt"
"sync"
"github.com/prometheus/common/model"
)
// MetricVec is a Collector to bundle metrics of the same name that
@ -25,10 +27,31 @@ import (
// provided in this package.
type MetricVec struct {
mtx sync.RWMutex // Protects the children.
children map[uint64]Metric
children map[uint64][]metricWithLabelValues
desc *Desc
newMetric func(labelValues ...string) Metric
hashAdd func(h uint64, s string) uint64 // replace hash function for testing collision handling
hashAddByte func(h uint64, b byte) uint64
}
// newMetricVec returns an initialized MetricVec. The concrete value is
// returned for embedding into another struct.
func newMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) MetricVec {
return MetricVec{
children: map[uint64][]metricWithLabelValues{},
desc: desc,
newMetric: newMetric,
hashAdd: hashAdd,
hashAddByte: hashAddByte,
}
}
// metricWithLabelValues provides the metric and its label values for
// disambiguation on hash collision.
type metricWithLabelValues struct {
values []string
metric Metric
}
// Describe implements Collector. The length of the returned slice
@ -42,8 +65,10 @@ func (m *MetricVec) Collect(ch chan<- Metric) {
m.mtx.RLock()
defer m.mtx.RUnlock()
for _, metric := range m.children {
ch <- metric
for _, metrics := range m.children {
for _, metric := range metrics {
ch <- metric.metric
}
}
}
@ -77,16 +102,7 @@ func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
return nil, err
}
m.mtx.RLock()
metric, ok := m.children[h]
m.mtx.RUnlock()
if ok {
return metric, nil
}
m.mtx.Lock()
defer m.mtx.Unlock()
return m.getOrCreateMetric(h, lvs...), nil
return m.getOrCreateMetric(h, lvs), nil
}
// GetMetricWith returns the Metric for the given Labels map (the label names
@ -107,20 +123,7 @@ func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
return nil, err
}
m.mtx.RLock()
metric, ok := m.children[h]
m.mtx.RUnlock()
if ok {
return metric, nil
}
lvs := make([]string, len(labels))
for i, label := range m.desc.variableLabels {
lvs[i] = labels[label]
}
m.mtx.Lock()
defer m.mtx.Unlock()
return m.getOrCreateMetric(h, lvs...), nil
return m.getOrCreateMetric(h, labels), nil
}
// WithLabelValues works as GetMetricWithLabelValues, but panics if an error
@ -168,11 +171,7 @@ func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
if err != nil {
return false
}
if _, ok := m.children[h]; !ok {
return false
}
delete(m.children, h)
return true
return m.deleteByHash(h, lvs)
}
// Delete deletes the metric where the variable labels are the same as those
@ -193,10 +192,31 @@ func (m *MetricVec) Delete(labels Labels) bool {
if err != nil {
return false
}
if _, ok := m.children[h]; !ok {
return m.deleteByHash(h, labels)
}
// deleteByHash removes the metric from the hash bucket h. If there are
// multiple matches in the bucket, use lvs to select a metric and remove only
// that metric.
//
// lvs MUST be of type Labels or []string or this method will panic.
func (m *MetricVec) deleteByHash(h uint64, values interface{}) bool {
metrics, ok := m.children[h]
if !ok {
return false
}
i := m.findMetric(metrics, values)
if i >= len(metrics) {
return false
}
if len(metrics) > 1 {
m.children[h] = append(metrics[:i], metrics[i+1:]...)
} else {
delete(m.children, h)
}
return true
}
@ -216,7 +236,8 @@ func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) {
}
h := hashNew()
for _, val := range vals {
h = hashAdd(h, val)
h = m.hashAdd(h, val)
h = m.hashAddByte(h, model.SeparatorByte)
}
return h, nil
}
@ -231,19 +252,125 @@ func (m *MetricVec) hashLabels(labels Labels) (uint64, error) {
if !ok {
return 0, fmt.Errorf("label name %q missing in label map", label)
}
h = hashAdd(h, val)
h = m.hashAdd(h, val)
h = m.hashAddByte(h, model.SeparatorByte)
}
return h, nil
}
func (m *MetricVec) getOrCreateMetric(hash uint64, labelValues ...string) Metric {
metric, ok := m.children[hash]
// getOrCreateMetric retrieves the metric by hash and label value or creates it
// and returns the new one.
//
// lvs MUST be of type Labels or []string or this method will panic.
//
// This function holds the mutex.
func (m *MetricVec) getOrCreateMetric(hash uint64, lvs interface{}) Metric {
m.mtx.RLock()
metric, ok := m.getMetric(hash, lvs)
m.mtx.RUnlock()
if ok {
return metric
}
m.mtx.Lock()
defer m.mtx.Unlock()
metric, ok = m.getMetric(hash, lvs)
if !ok {
// Copy labelValues. Otherwise, they would be allocated even if we don't go
// down this code path.
copiedLabelValues := append(make([]string, 0, len(labelValues)), labelValues...)
metric = m.newMetric(copiedLabelValues...)
m.children[hash] = metric
lvs := m.copyLabelValues(lvs)
metric = m.newMetric(lvs...)
m.children[hash] = append(m.children[hash], metricWithLabelValues{values: lvs, metric: metric})
}
return metric
}
// getMetric while handling possible collisions in the hash space. Must be
// called while holding read mutex.
//
// lvs must be of type Labels or []string.
func (m *MetricVec) getMetric(h uint64, lvs interface{}) (Metric, bool) {
metrics, ok := m.children[h]
if ok {
return m.selectMetric(metrics, lvs)
}
return nil, false
}
func (m *MetricVec) selectMetric(metrics []metricWithLabelValues, lvs interface{}) (Metric, bool) {
i := m.findMetric(metrics, lvs)
if i < len(metrics) {
return metrics[i].metric, true
}
return nil, false
}
// findMetric returns the index of the matching metric or len(metrics) if not
// found.
func (m *MetricVec) findMetric(metrics []metricWithLabelValues, lvs interface{}) int {
for i, metric := range metrics {
if m.matchLabels(metric.values, lvs) {
return i
}
}
return len(metrics)
}
func (m *MetricVec) matchLabels(values []string, lvs interface{}) bool {
switch lvs := lvs.(type) {
case []string:
if len(values) != len(lvs) {
return false
}
for i, v := range values {
if v != lvs[i] {
return false
}
}
return true
case Labels:
if len(lvs) != len(values) {
return false
}
for i, k := range m.desc.variableLabels {
if values[i] != lvs[k] {
return false
}
}
return true
default:
// If we reach this condition, there is an unexpected type being used
// as a labels value. Either add branch here for the new type or fix
// the bug causing the type to be passed in.
panic("unsupported type")
}
}
// copyLabelValues copies the labels values into common string slice format to
// use when allocating the metric and to keep track of hash collision
// ambiguity.
//
// lvs must be of type Labels or []string or this method will panic.
func (m *MetricVec) copyLabelValues(lvs interface{}) []string {
var labelValues []string
switch lvs := lvs.(type) {
case []string:
labelValues = make([]string, len(lvs))
copy(labelValues, lvs)
case Labels:
labelValues = make([]string, len(lvs))
for i, k := range m.desc.variableLabels {
labelValues[i] = lvs[k]
}
default:
panic(fmt.Sprintf("unsupported type for lvs: %#v", lvs))
}
return labelValues
}

188
prometheus/vec_test.go
View File

@ -14,19 +14,25 @@
package prometheus
import (
"fmt"
"testing"
dto "github.com/prometheus/client_model/go"
)
func TestDelete(t *testing.T) {
desc := NewDesc("test", "helpless", []string{"l1", "l2"}, nil)
vec := MetricVec{
children: map[uint64]Metric{},
desc: desc,
newMetric: func(lvs ...string) Metric {
return newValue(desc, UntypedValue, 0, lvs...)
},
}
vec := newUntypedMetricVec("test", "helpless", []string{"l1", "l2"})
testDelete(t, vec)
}
func TestDeleteWithCollisions(t *testing.T) {
vec := newUntypedMetricVec("test", "helpless", []string{"l1", "l2"})
vec.hashAdd = func(h uint64, s string) uint64 { return 1 }
vec.hashAddByte = func(h uint64, b byte) uint64 { return 1 }
testDelete(t, vec)
}
func testDelete(t *testing.T, vec *MetricVec) {
if got, want := vec.Delete(Labels{"l1": "v1", "l2": "v2"}), false; got != want {
t.Errorf("got %v, want %v", got, want)
}
@ -57,28 +63,36 @@ func TestDelete(t *testing.T) {
}
func TestDeleteLabelValues(t *testing.T) {
desc := NewDesc("test", "helpless", []string{"l1", "l2"}, nil)
vec := MetricVec{
children: map[uint64]Metric{},
desc: desc,
newMetric: func(lvs ...string) Metric {
return newValue(desc, UntypedValue, 0, lvs...)
},
}
vec := newUntypedMetricVec("test", "helpless", []string{"l1", "l2"})
testDeleteLabelValues(t, vec)
}
func TestDeleteLabelValuesWithCollisions(t *testing.T) {
vec := newUntypedMetricVec("test", "helpless", []string{"l1", "l2"})
vec.hashAdd = func(h uint64, s string) uint64 { return 1 }
vec.hashAddByte = func(h uint64, b byte) uint64 { return 1 }
testDeleteLabelValues(t, vec)
}
func testDeleteLabelValues(t *testing.T, vec *MetricVec) {
if got, want := vec.DeleteLabelValues("v1", "v2"), false; got != want {
t.Errorf("got %v, want %v", got, want)
}
vec.With(Labels{"l1": "v1", "l2": "v2"}).(Untyped).Set(42)
vec.With(Labels{"l1": "v1", "l2": "v3"}).(Untyped).Set(42) // add junk data for collision
if got, want := vec.DeleteLabelValues("v1", "v2"), true; got != want {
t.Errorf("got %v, want %v", got, want)
}
if got, want := vec.DeleteLabelValues("v1", "v2"), false; got != want {
t.Errorf("got %v, want %v", got, want)
}
if got, want := vec.DeleteLabelValues("v1", "v3"), true; got != want {
t.Errorf("got %v, want %v", got, want)
}
vec.With(Labels{"l1": "v1", "l2": "v2"}).(Untyped).Set(42)
// delete out of order
if got, want := vec.DeleteLabelValues("v2", "v1"), false; got != want {
t.Errorf("got %v, want %v", got, want)
}
@ -86,3 +100,145 @@ func TestDeleteLabelValues(t *testing.T) {
t.Errorf("got %v, want %v", got, want)
}
}
func TestMetricVec(t *testing.T) {
vec := newUntypedMetricVec("test", "helpless", []string{"l1", "l2"})
testMetricVec(t, vec)
}
func TestMetricVecWithCollisions(t *testing.T) {
vec := newUntypedMetricVec("test", "helpless", []string{"l1", "l2"})
vec.hashAdd = func(h uint64, s string) uint64 { return 1 }
vec.hashAddByte = func(h uint64, b byte) uint64 { return 1 }
testMetricVec(t, vec)
}
func testMetricVec(t *testing.T, vec *MetricVec) {
vec.Reset() // actually test Reset now!
var pair [2]string
// keep track of metrics
expected := map[[2]string]int{}
for i := 0; i < 1000; i++ {
pair[0], pair[1] = fmt.Sprint(i%4), fmt.Sprint(i%5) // varying combinations multiples
expected[pair]++
vec.WithLabelValues(pair[0], pair[1]).(Untyped).Inc()
expected[[2]string{"v1", "v2"}]++
vec.WithLabelValues("v1", "v2").(Untyped).Inc()
}
var total int
for _, metrics := range vec.children {
for _, metric := range metrics {
total++
copy(pair[:], metric.values)
// is there a better way to access the value of a metric?
var metricOut dto.Metric
metric.metric.Write(&metricOut)
actual := *metricOut.Untyped.Value
var actualPair [2]string
for i, label := range metricOut.Label {
actualPair[i] = *label.Value
}
// test output pair against metric.values to ensure we've selected
// the right one. We check this to ensure the below check means
// anything at all.
if actualPair != pair {
t.Fatalf("unexpected pair association in metric map: %v != %v", actualPair, pair)
}
if actual != float64(expected[pair]) {
t.Fatalf("incorrect counter value for %v: %v != %v", pair, actual, expected[pair])
}
}
}
if total != len(expected) {
t.Fatalf("unexpected number of metrics: %v != %v", total, len(expected))
}
vec.Reset()
if len(vec.children) > 0 {
t.Fatalf("reset failed")
}
}
func newUntypedMetricVec(name, help string, labels []string) *MetricVec {
desc := NewDesc("test", "helpless", labels, nil)
vec := newMetricVec(desc, func(lvs ...string) Metric {
return newValue(desc, UntypedValue, 0, lvs...)
})
return &vec
}
func BenchmarkMetricVecWithLabelValuesBasic(B *testing.B) {
benchmarkMetricVecWithLabelValues(B, map[string][]string{
"l1": []string{"onevalue"},
"l2": []string{"twovalue"},
})
}
func BenchmarkMetricVecWithLabelValues2Keys10ValueCardinality(B *testing.B) {
benchmarkMetricVecWithLabelValuesCardinality(B, 2, 10)
}
func BenchmarkMetricVecWithLabelValues4Keys10ValueCardinality(B *testing.B) {
benchmarkMetricVecWithLabelValuesCardinality(B, 4, 10)
}
func BenchmarkMetricVecWithLabelValues2Keys100ValueCardinality(B *testing.B) {
benchmarkMetricVecWithLabelValuesCardinality(B, 2, 100)
}
func BenchmarkMetricVecWithLabelValues10Keys100ValueCardinality(B *testing.B) {
benchmarkMetricVecWithLabelValuesCardinality(B, 10, 100)
}
func BenchmarkMetricVecWithLabelValues10Keys1000ValueCardinality(B *testing.B) {
benchmarkMetricVecWithLabelValuesCardinality(B, 10, 1000)
}
func benchmarkMetricVecWithLabelValuesCardinality(B *testing.B, nkeys, nvalues int) {
labels := map[string][]string{}
for i := 0; i < nkeys; i++ {
var (
k = fmt.Sprintf("key-%v", i)
vs = make([]string, 0, nvalues)
)
for j := 0; j < nvalues; j++ {
vs = append(vs, fmt.Sprintf("value-%v", j))
}
labels[k] = vs
}
benchmarkMetricVecWithLabelValues(B, labels)
}
func benchmarkMetricVecWithLabelValues(B *testing.B, labels map[string][]string) {
var keys []string
for k := range labels { // map order dependent, who cares though
keys = append(keys, k)
}
values := make([]string, len(labels)) // value cache for permutations
vec := newUntypedMetricVec("test", "helpless", keys)
B.ReportAllocs()
B.ResetTimer()
for i := 0; i < B.N; i++ {
// varies input across provide map entries based on key size.
for j, k := range keys {
candidates := labels[k]
values[j] = candidates[i%len(candidates)]
}
vec.WithLabelValues(values...)
}
}