Optimize fingerprint comparison time.

model/fingerprinting.go

@@ -152,7 +152,37 @@ func (f fingerprint) LastCharacterOfLastLabelValue() string {
 }
 
 func (f fingerprint) Less(o Fingerprint) bool {
-	return f.String() < o.String()
+	// BUG(julius): Deprecate Fingerprint interface and clean this up.
+	fp := o.(fingerprint)
+
+	if f.hash < fp.hash {
+		return true
+	}
+	if f.hash > fp.hash {
+		return false
+	}
+
+	if f.firstCharacterOfFirstLabelName < fp.firstCharacterOfFirstLabelName {
+		return true
+	}
+	if f.firstCharacterOfFirstLabelName > fp.firstCharacterOfFirstLabelName {
+		return false
+	}
+
+	if f.labelMatterLength < fp.labelMatterLength {
+		return true
+	}
+	if f.labelMatterLength > fp.labelMatterLength {
+		return false
+	}
+
+	if f.lastCharacterOfLastLabelValue < fp.lastCharacterOfLastLabelValue {
+		return true
+	}
+	if f.lastCharacterOfLastLabelValue > fp.lastCharacterOfLastLabelValue {
+		return false
+	}
+	return false
 }
 
 func (f fingerprint) Equal(o Fingerprint) (equal bool) {

model/fingerprinting_test.go

@@ -14,6 +14,7 @@
 package model
 
 import (
+	"runtime"
 	"testing"
 )
 
@@ -66,3 +67,38 @@ func TestFingerprintComparison(t *testing.T) {
 		}
 	}
 }
+
+func BenchmarkFingerprinting(b *testing.B) {
+	b.StopTimer()
+	fps := []fingerprint{
+		{
+			hash: 0,
+			firstCharacterOfFirstLabelName: "a",
+			labelMatterLength:              2,
+			lastCharacterOfLastLabelValue:  "z",
+		},
+		{
+			hash: 0,
+			firstCharacterOfFirstLabelName: "a",
+			labelMatterLength:              2,
+			lastCharacterOfLastLabelValue:  "z",
+		},
+	}
+	for i := 0; i < 10; i++ {
+		fps[0].Less(fps[1])
+	}
+	b.Logf("N: %v", b.N)
+	b.StartTimer()
+
+	var pre runtime.MemStats
+	runtime.ReadMemStats(&pre)
+
+	for i := 0; i < b.N; i++ {
+		fps[0].Less(fps[1])
+	}
+
+	var post runtime.MemStats
+	runtime.ReadMemStats(&post)
+
+	b.Logf("allocs: %d items: ", post.TotalAlloc-pre.TotalAlloc)
+}