pkg/metrics: add "RequestsSummaryCompare"

Signed-off-by: Gyuho Lee <leegyuho@amazon.com>

pkg/metrics/metrics.go

@@ -14,6 +14,89 @@ import (
 	dto "github.com/prometheus/client_model/go"
 )
 
+// RequestsSummaryCompare compares two "RequestsSummary".
+// Delta is computed with "A" as "before" and with "B" as "after".
+type RequestsSummaryCompare struct {
+	A RequestsSummary `json:"a" read-only:"true"`
+	B RequestsSummary `json:"b" read-only:"true"`
+
+	LantencyP50DeltaPercent   float64 `json:"latency-p50-delta-percent" read-only:"true"`
+	LantencyP90DeltaPercent   float64 `json:"latency-p90-delta-percent" read-only:"true"`
+	LantencyP99DeltaPercent   float64 `json:"latency-p99-delta-percent" read-only:"true"`
+	LantencyP999DeltaPercent  float64 `json:"latency-p99.9-delta-percent" read-only:"true"`
+	LantencyP9999DeltaPercent float64 `json:"latency-p99.99-delta-percent" read-only:"true"`
+}
+
+func (c RequestsSummaryCompare) Table() string {
+	buf := bytes.NewBuffer(nil)
+	tb := tablewriter.NewWriter(buf)
+	tb.SetAutoWrapText(false)
+	tb.SetColWidth(1500)
+	tb.SetCenterSeparator("*")
+	tb.SetAlignment(tablewriter.ALIGN_CENTER)
+	tb.SetCaption(true, "(% delta from 'A' to 'B')")
+	tb.SetHeader([]string{"Percentile", fmt.Sprintf("A %q", c.A.TestID), fmt.Sprintf("B %q", c.B.TestID), "Delta"})
+
+	tb.Append([]string{"50-pct Latency", c.A.LantencyP50.String(), c.B.LantencyP50.String(), toPercent(c.LantencyP50DeltaPercent)})
+	tb.Append([]string{"90-pct Latency", c.A.LantencyP90.String(), c.B.LantencyP90.String(), toPercent(c.LantencyP90DeltaPercent)})
+	tb.Append([]string{"99-pct Latency", c.A.LantencyP99.String(), c.B.LantencyP99.String(), toPercent(c.LantencyP99DeltaPercent)})
+	tb.Append([]string{"99.9-pct Latency", c.A.LantencyP999.String(), c.B.LantencyP999.String(), toPercent(c.LantencyP999DeltaPercent)})
+	tb.Append([]string{"99.99-pct Latency", c.A.LantencyP9999.String(), c.B.LantencyP9999.String(), toPercent(c.LantencyP9999DeltaPercent)})
+
+	tb.Render()
+	return buf.String()
+}
+
+func toPercent(f float64) string {
+	sign := "+"
+	if f < 0.0 {
+		sign = ""
+	}
+	return fmt.Sprintf("%s%.3f %%", sign, f)
+}
+
+// CompareRequestsSummary compares two "RequestsSummary".
+func CompareRequestsSummary(a RequestsSummary, b RequestsSummary) (c RequestsSummaryCompare, err error) {
+	if len(a.LatencyHistogram) != len(b.LatencyHistogram) {
+		return RequestsSummaryCompare{}, fmt.Errorf("len(a.LatencyHistogram) %d != len(b.LatencyHistogram) %d", len(a.LatencyHistogram), len(b.LatencyHistogram))
+	}
+
+	c = RequestsSummaryCompare{
+		A: a,
+		B: b,
+	}
+
+	// e.g. "A" 100, "B" 50 == -50%
+	// e.g. "A" 50, "B" 100 == 100%
+	deltaP50 := float64(b.LantencyP50) - float64(a.LantencyP50)
+	deltaP50 /= float64(a.LantencyP50)
+	deltaP50 *= 100.0
+
+	deltaP90 := float64(b.LantencyP90) - float64(a.LantencyP90)
+	deltaP90 /= float64(a.LantencyP90)
+	deltaP90 *= 100.0
+
+	deltaP99 := float64(b.LantencyP99) - float64(a.LantencyP99)
+	deltaP99 /= float64(a.LantencyP99)
+	deltaP99 *= 100.0
+
+	deltaP999 := float64(b.LantencyP999) - float64(a.LantencyP999)
+	deltaP999 /= float64(a.LantencyP999)
+	deltaP999 *= 100.0
+
+	deltaP9999 := float64(b.LantencyP9999) - float64(a.LantencyP9999)
+	deltaP9999 /= float64(a.LantencyP9999)
+	deltaP9999 *= 100.0
+
+	c.LantencyP50DeltaPercent = deltaP50
+	c.LantencyP90DeltaPercent = deltaP90
+	c.LantencyP99DeltaPercent = deltaP99
+	c.LantencyP999DeltaPercent = deltaP999
+	c.LantencyP9999DeltaPercent = deltaP9999
+
+	return c, nil
+}
+
 // RequestsSummary represents request results.
 type RequestsSummary struct {
 	// TestID is the test ID.

pkg/metrics/metrics_test.go

@@ -3,6 +3,7 @@ package metrics
 import (
 	"fmt"
 	"math"
+	"math/rand"
 	"reflect"
 	"sort"
 	"testing"
@@ -12,21 +13,66 @@ import (
 )
 
 func TestRequestsSummary(t *testing.T) {
-	ds := make(Durations, 20000)
+	ds1 := make(Durations, 20000)
 	for i := 0; i < 20000; i++ {
 		sign := 1
 		if i%2 == 0 {
 			sign = -1
 		}
+		delta := time.Duration(rand.Int63n(500)) * time.Millisecond
 		dur := time.Second + time.Duration(sign*i)*time.Millisecond
 		if dur < 0 {
 			dur = 2 * time.Second
 		}
-		ds[20000-1-i] = dur
+		ds1[20000-1-i] = dur + delta
 	}
-	sort.Sort(ds)
+	sort.Sort(ds1)
+	rs1 := RequestsSummary{
+		TestID:       time.Now().UTC().Format(time.RFC3339Nano),
+		SuccessTotal: 10,
+		FailureTotal: 10,
+		LatencyHistogram: HistogramBuckets([]HistogramBucket{
+			{Scale: "milliseconds", LowerBound: 0, UpperBound: 0.5, Count: 0},
+			{Scale: "milliseconds", LowerBound: 0.5, UpperBound: 1, Count: 2},
+			{Scale: "milliseconds", LowerBound: 1, UpperBound: 2, Count: 0},
+			{Scale: "milliseconds", LowerBound: 2, UpperBound: 4, Count: 0},
+			{Scale: "milliseconds", LowerBound: 4, UpperBound: 8, Count: 0},
+			{Scale: "milliseconds", LowerBound: 8, UpperBound: 16, Count: 8},
+			{Scale: "milliseconds", LowerBound: 16, UpperBound: 32, Count: 0},
+			{Scale: "milliseconds", LowerBound: 32, UpperBound: 64, Count: 100},
+			{Scale: "milliseconds", LowerBound: 64, UpperBound: 128, Count: 0},
+			{Scale: "milliseconds", LowerBound: 128, UpperBound: 256, Count: 0},
+			{Scale: "milliseconds", LowerBound: 256, UpperBound: 512, Count: 20},
+			{Scale: "milliseconds", LowerBound: 512, UpperBound: 1024, Count: 0},
+			{Scale: "milliseconds", LowerBound: 1024, UpperBound: 2048, Count: 0},
+			{Scale: "milliseconds", LowerBound: 2048, UpperBound: 4096, Count: 0},
+			{Scale: "milliseconds", LowerBound: 4096, UpperBound: math.MaxFloat64, Count: 4},
+		}),
+		LantencyP50:   ds1.PickLantencyP50(),
+		LantencyP90:   ds1.PickLantencyP90(),
+		LantencyP99:   ds1.PickLantencyP99(),
+		LantencyP999:  ds1.PickLantencyP999(),
+		LantencyP9999: ds1.PickLantencyP9999(),
+	}
+	fmt.Println(rs1.JSON())
+	fmt.Println(rs1.Table())
 
-	rs := RequestsSummary{
+	println()
+	ds2 := make(Durations, 20000)
+	for i := 0; i < 20000; i++ {
+		sign := 1
+		if i%2 == 0 {
+			sign = -1
+		}
+		delta := time.Duration(rand.Int63n(500)) * time.Millisecond
+		dur := time.Second + time.Duration(sign*i)*time.Millisecond
+		if dur < 0 {
+			dur = 2 * time.Second
+		}
+		ds2[20000-1-i] = dur + delta
+	}
+	sort.Sort(ds2)
+	rs2 := RequestsSummary{
 		TestID:       time.Now().UTC().Format(time.RFC3339Nano),
 		SuccessTotal: 10,
 		FailureTotal: 10,
@@ -47,14 +93,21 @@ func TestRequestsSummary(t *testing.T) {
 			{Scale: "milliseconds", LowerBound: 2048, UpperBound: 4096, Count: 0},
 			{Scale: "milliseconds", LowerBound: 4096, UpperBound: math.MaxFloat64, Count: 4},
 		}),
-		LantencyP50:   ds.PickLantencyP50(),
-		LantencyP90:   ds.PickLantencyP90(),
-		LantencyP99:   ds.PickLantencyP99(),
-		LantencyP999:  ds.PickLantencyP999(),
-		LantencyP9999: ds.PickLantencyP9999(),
+		LantencyP50:   ds2.PickLantencyP50(),
+		LantencyP90:   ds2.PickLantencyP90(),
+		LantencyP99:   ds2.PickLantencyP99(),
+		LantencyP999:  ds2.PickLantencyP999(),
+		LantencyP9999: ds2.PickLantencyP9999(),
+	}
+	fmt.Println(rs2.JSON())
+	fmt.Println(rs2.Table())
+
+	println()
+	c, err := CompareRequestsSummary(rs1, rs2)
+	if err != nil {
+		t.Fatal(err)
 	}
-	fmt.Println(rs.JSON())
-	fmt.Println(rs.Table())
+	fmt.Println(c.Table())
 }
 
 func TestMetricsHistogram(t *testing.T) {