fastdto attempt.

Signed-off-by: bwplotka <bwplotka@gmail.com>

Author: bwplotka

prometheus/counter.go

@@ -19,6 +19,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus/internal/fastdto"
 	dto "github.com/prometheus/client_model/go"
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
@@ -94,7 +95,7 @@ func NewCounter(opts CounterOpts) Counter {
 	if opts.now == nil {
 		opts.now = time.Now
 	}
-	result := &counter{desc: desc, labelPairs: desc.labelPairs, now: opts.now}
+	result := &counter{desc: desc, labelPairs: fastdto.ToDTOLabelPair(desc.labelPairs), now: opts.now}
 	result.init(result) // Init self-collection.
 	result.createdTs = timestamppb.New(opts.now())
 	return result

prometheus/desc.go

@@ -19,11 +19,8 @@ import (
 	"strings"
 
 	"github.com/cespare/xxhash/v2"
-	dto "github.com/prometheus/client_model/go"
+	"github.com/prometheus/client_golang/prometheus/internal/fastdto"
 	"github.com/prometheus/common/model"
-	"google.golang.org/protobuf/proto"
-
-	"github.com/prometheus/client_golang/prometheus/internal"
 )
 
 // Desc is the descriptor used by every Prometheus Metric. It is essentially
@@ -56,7 +53,7 @@ type Desc struct {
 	variableLabelOrder []int
 	// labelPairs contains the sorted DTO label pairs based on the constant labels
 	// and variable labels
-	labelPairs []*dto.LabelPair
+	labelPairs []fastdto.LabelPair
 	// id is a hash of the values of the ConstLabels and fqName. This
 	// must be unique among all registered descriptors and can therefore be
 	// used as an identifier of the descriptor.
@@ -164,24 +161,23 @@ func (v2) NewDesc(fqName, help string, variableLabels ConstrainableLabels, const
 	}
 	d.dimHash = xxh.Sum64()
 
-	d.labelPairs = make([]*dto.LabelPair, 0, len(constLabels)+len(d.variableLabels.names))
+	d.labelPairs = make([]fastdto.LabelPair, len(constLabels)+len(d.variableLabels.names))
+	i := 0
 	for n, v := range constLabels {
-		d.labelPairs = append(d.labelPairs, &dto.LabelPair{
-			Name:  proto.String(n),
-			Value: proto.String(v),
-		})
+		d.labelPairs[i].Name = n
+		d.labelPairs[i].Value = v
+		i++
 	}
 	for _, labelName := range d.variableLabels.names {
-		d.labelPairs = append(d.labelPairs, &dto.LabelPair{
-			Name: proto.String(labelName),
-		})
+		d.labelPairs[i].Name = labelName
+		i++
 	}
-	sort.Sort(internal.LabelPairSorter(d.labelPairs))
+	sort.Sort(fastdto.LabelPairSorter(d.labelPairs))
 
 	d.variableLabelOrder = make([]int, len(d.variableLabels.names))
 	for outputIndex, pair := range d.labelPairs {
 		// Constant labels have values variable labels do not.
-		if pair.Value != nil {
+		if pair.Value != "" {
 			continue
 		}
 		for sourceIndex, variableLabel := range d.variableLabels.names {
@@ -190,7 +186,6 @@ func (v2) NewDesc(fqName, help string, variableLabels ConstrainableLabels, const
 			}
 		}
 	}
-
 	return d
 }
 
@@ -207,7 +202,7 @@ func NewInvalidDesc(err error) *Desc {
 func (d *Desc) String() string {
 	lpStrings := make([]string, 0, len(d.labelPairs))
 	for _, lp := range d.labelPairs {
-		if lp.Value == nil {
+		if lp.Value == "" {
 			continue
 		}
 		lpStrings = append(

prometheus/desc_test.go

@@ -63,6 +63,18 @@ func TestNewInvalidDesc_String(t *testing.T) {
 	}
 }
 
+/*
+ export bench=newDesc && go test ./prometheus \
+	-run '^$' -bench '^BenchmarkNewDesc/labels=10' \
+	-benchtime 5s -benchmem -cpu 2 -timeout 999m \
+	-memprofile=${bench}.mem.pprof \
+	| tee ${bench}.txt
+
+ export bench=newDesc-v2 && go test ./prometheus \
+	-run '^$' -bench '^BenchmarkNewDesc' \
+	-benchtime 5s -benchmem -count=6 -cpu 2 -timeout 999m \
+	| tee ${bench}.txt
+*/
 func BenchmarkNewDesc(b *testing.B) {
 	for _, bm := range []struct {
 		labelCount int
@@ -82,6 +94,8 @@ func BenchmarkNewDesc(b *testing.B) {
 		},
 	} {
 		b.Run(fmt.Sprintf("labels=%v", bm.labelCount), func(b *testing.B) {
+			b.ReportAllocs()
+			b.ResetTimer()
 			for i := 0; i < b.N; i++ {
 				bm.descFunc()
 			}

prometheus/gauge.go

@@ -18,6 +18,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/prometheus/client_golang/prometheus/internal/fastdto"
 	dto "github.com/prometheus/client_model/go"
 )
 
@@ -82,7 +83,7 @@ func NewGauge(opts GaugeOpts) Gauge {
 		nil,
 		opts.ConstLabels,
 	)
-	result := &gauge{desc: desc, labelPairs: desc.labelPairs}
+	result := &gauge{desc: desc, labelPairs: fastdto.ToDTOLabelPair(desc.labelPairs)}
 	result.init(result) // Init self-collection.
 	return result
 }

prometheus/histogram.go

@@ -956,13 +956,13 @@ func (h *histogram) limitBuckets(counts *histogramCounts, value float64, bucket
 // h.nativeHistogramMinResetDuration has been passed. It returns true if the
 // histogram has been reset. The caller must have locked h.mtx.
 func (h *histogram) maybeReset(
-	hot, cold *histogramCounts, coldIdx uint64, value float64, bucket int,
+		hot, cold *histogramCounts, coldIdx uint64, value float64, bucket int,
 ) bool {
 	// We are using the possibly mocked h.now() rather than
 	// time.Since(h.lastResetTime) to enable testing.
 	if h.nativeHistogramMinResetDuration == 0 || // No reset configured.
-		h.resetScheduled || // Do not interefere if a reset is already scheduled.
-		h.now().Sub(h.lastResetTime) < h.nativeHistogramMinResetDuration {
+			h.resetScheduled || // Do not interefere if a reset is already scheduled.
+			h.now().Sub(h.lastResetTime) < h.nativeHistogramMinResetDuration {
 		return false
 	}
 	// Completely reset coldCounts.
@@ -1355,11 +1355,11 @@ func (h *constHistogram) Write(out *dto.Metric) error {
 // NewConstHistogram returns an error if the length of labelValues is not
 // consistent with the variable labels in Desc or if Desc is invalid.
 func NewConstHistogram(
-	desc *Desc,
-	count uint64,
-	sum float64,
-	buckets map[float64]uint64,
-	labelValues ...string,
+		desc *Desc,
+		count uint64,
+		sum float64,
+		buckets map[float64]uint64,
+		labelValues ...string,
 ) (Metric, error) {
 	if desc.err != nil {
 		return nil, desc.err
@@ -1379,11 +1379,11 @@ func NewConstHistogram(
 // MustNewConstHistogram is a version of NewConstHistogram that panics where
 // NewConstHistogram would have returned an error.
 func MustNewConstHistogram(
-	desc *Desc,
-	count uint64,
-	sum float64,
-	buckets map[float64]uint64,
-	labelValues ...string,
+		desc *Desc,
+		count uint64,
+		sum float64,
+		buckets map[float64]uint64,
+		labelValues ...string,
 ) Metric {
 	m, err := NewConstHistogram(desc, count, sum, buckets, labelValues...)
 	if err != nil {
@@ -1394,12 +1394,12 @@ func MustNewConstHistogram(
 
 // NewConstHistogramWithCreatedTimestamp does the same thing as NewConstHistogram but sets the created timestamp.
 func NewConstHistogramWithCreatedTimestamp(
-	desc *Desc,
-	count uint64,
-	sum float64,
-	buckets map[float64]uint64,
-	ct time.Time,
-	labelValues ...string,
+		desc *Desc,
+		count uint64,
+		sum float64,
+		buckets map[float64]uint64,
+		ct time.Time,
+		labelValues ...string,
 ) (Metric, error) {
 	if desc.err != nil {
 		return nil, desc.err
@@ -1420,12 +1420,12 @@ func NewConstHistogramWithCreatedTimestamp(
 // MustNewConstHistogramWithCreatedTimestamp is a version of NewConstHistogramWithCreatedTimestamp that panics where
 // NewConstHistogramWithCreatedTimestamp would have returned an error.
 func MustNewConstHistogramWithCreatedTimestamp(
-	desc *Desc,
-	count uint64,
-	sum float64,
-	buckets map[float64]uint64,
-	ct time.Time,
-	labelValues ...string,
+		desc *Desc,
+		count uint64,
+		sum float64,
+		buckets map[float64]uint64,
+		ct time.Time,
+		labelValues ...string,
 ) Metric {
 	m, err := NewConstHistogramWithCreatedTimestamp(desc, count, sum, buckets, ct, labelValues...)
 	if err != nil {
@@ -1873,7 +1873,7 @@ func validateCount(sum float64, count uint64, negativeBuckets, positiveBuckets m
 	// Otherwise, the number of observations must be equal to the sum of all bucket counts .
 
 	if math.IsNaN(sum) && bucketPopulationSum > int64(count) ||
-		!math.IsNaN(sum) && bucketPopulationSum != int64(count) {
+			!math.IsNaN(sum) && bucketPopulationSum != int64(count) {
 		return errors.New("the sum of all bucket populations exceeds the count of observations")
 	}
 	return nil
@@ -1902,15 +1902,15 @@ func validateCount(sum float64, count uint64, negativeBuckets, positiveBuckets m
 //
 // See https://opentelemetry.io/docs/specs/otel/compatibility/prometheus_and_openmetrics/#exponential-histograms for more details about the conversion from OTel to Prometheus.
 func NewConstNativeHistogram(
-	desc *Desc,
-	count uint64,
-	sum float64,
-	positiveBuckets, negativeBuckets map[int]int64,
-	zeroBucket uint64,
-	schema int32,
-	zeroThreshold float64,
-	createdTimestamp time.Time,
-	labelValues ...string,
+		desc *Desc,
+		count uint64,
+		sum float64,
+		positiveBuckets, negativeBuckets map[int]int64,
+		zeroBucket uint64,
+		schema int32,
+		zeroThreshold float64,
+		createdTimestamp time.Time,
+		labelValues ...string,
 ) (Metric, error) {
 	if desc.err != nil {
 		return nil, desc.err
@@ -1958,15 +1958,15 @@ func NewConstNativeHistogram(
 // MustNewConstNativeHistogram is a version of NewConstNativeHistogram that panics where
 // NewConstNativeHistogram would have returned an error.
 func MustNewConstNativeHistogram(
-	desc *Desc,
-	count uint64,
-	sum float64,
-	positiveBuckets, negativeBuckets map[int]int64,
-	zeroBucket uint64,
-	nativeHistogramSchema int32,
-	nativeHistogramZeroThreshold float64,
-	createdTimestamp time.Time,
-	labelValues ...string,
+		desc *Desc,
+		count uint64,
+		sum float64,
+		positiveBuckets, negativeBuckets map[int]int64,
+		zeroBucket uint64,
+		nativeHistogramSchema int32,
+		nativeHistogramZeroThreshold float64,
+		createdTimestamp time.Time,
+		labelValues ...string,
 ) Metric {
 	nativehistogram, err := NewConstNativeHistogram(desc,
 		count,

prometheus/internal/fastdto/labels.go

@@ -0,0 +1,45 @@
+package fastdto
+
+import (
+	dto "github.com/prometheus/client_model/go"
+)
+
+type LabelPair struct {
+	Name  string `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
+	Value string `protobuf:"bytes,2,opt,name=value" json:"value,omitempty"`
+}
+
+func (p LabelPair) GetName() string {
+	return p.Name
+}
+
+func (p LabelPair) GetValue() string {
+	return p.Value
+}
+
+// LabelPairSorter implements sort.Interface. It is used to sort a slice of
+// LabelPairs
+type LabelPairSorter []LabelPair
+
+func (s LabelPairSorter) Len() int {
+	return len(s)
+}
+
+func (s LabelPairSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s LabelPairSorter) Less(i, j int) bool {
+	return s[i].Name < s[j].Name
+}
+
+func ToDTOLabelPair(in []LabelPair) []*dto.LabelPair {
+	ret := make([]*dto.LabelPair, len(in))
+	for i := range in {
+		ret[i] = &dto.LabelPair{
+			Name:  &(in[i].Name),
+			Value: &(in[i].Value),
+		}
+	}
+	return ret
+}

prometheus/internal/fastdto/labels_test.go

@@ -0,0 +1,58 @@
+package fastdto
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+	dto "github.com/prometheus/client_model/go"
+	"google.golang.org/protobuf/proto"
+)
+
+func BenchmarkToDTOLabelPairs(b *testing.B) {
+	test := []LabelPair{
+		{"foo", "bar"},
+		{"foo2", "bar2"},
+		{"foo3", "bar3"},
+	}
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = ToDTOLabelPair(test)
+	}
+}
+
+func TestLabelPairSorter(t *testing.T) {
+	test := []LabelPair{
+		{"foo3", "bar3"},
+		{"foo", "bar"},
+		{"foo2", "bar2"},
+	}
+	sort.Sort(LabelPairSorter(test))
+
+	expected := []LabelPair{
+		{"foo", "bar"},
+		{"foo2", "bar2"},
+		{"foo3", "bar3"},
+	}
+	if diff := cmp.Diff(test, expected); diff != "" {
+		t.Fatal(diff)
+	}
+}
+
+func TestToDTOLabelPair(t *testing.T) {
+	test := []LabelPair{
+		{"foo", "bar"},
+		{"foo2", "bar2"},
+		{"foo3", "bar3"},
+	}
+	expected := []*dto.LabelPair{
+		{Name: proto.String("foo"), Value: proto.String("bar")},
+		{Name: proto.String("foo2"), Value: proto.String("bar2")},
+		{Name: proto.String("foo3"), Value: proto.String("bar3")},
+	}
+	if diff := cmp.Diff(ToDTOLabelPair(test), expected, cmpopts.IgnoreUnexported(dto.LabelPair{})); diff != "" {
+		t.Fatal(diff)
+	}
+}