tools: rewrite benchmark tool

tools/benchmark/cmd/report.go

@@ -0,0 +1,156 @@
+// Copyright 2014 Google Inc. All Rights Reserved.
+//
+// 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.
+
+// the file is borrowed from github.com/rakyll/boom/boomer/print.go
+
+package cmd
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+)
+
+const (
+	barChar = "∎"
+)
+
+type result struct {
+	errStr   string
+	duration time.Duration
+}
+
+type report struct {
+	avgTotal float64
+	fastest  float64
+	slowest  float64
+	average  float64
+	rps      float64
+
+	results chan *result
+	total   time.Duration
+
+	errorDist map[string]int
+	lats      []float64
+}
+
+func printReport(size int, results chan *result, total time.Duration) {
+	r := &report{
+		results:   results,
+		total:     total,
+		errorDist: make(map[string]int),
+	}
+	r.finalize()
+}
+
+func (r *report) finalize() {
+	for {
+		select {
+		case res := <-r.results:
+			if res.errStr != "" {
+				r.errorDist[res.errStr]++
+			} else {
+				r.lats = append(r.lats, res.duration.Seconds())
+				r.avgTotal += res.duration.Seconds()
+			}
+		default:
+			r.rps = float64(len(r.lats)) / r.total.Seconds()
+			r.average = r.avgTotal / float64(len(r.lats))
+			r.print()
+			return
+		}
+	}
+}
+
+func (r *report) print() {
+	sort.Float64s(r.lats)
+
+	if len(r.lats) > 0 {
+		r.fastest = r.lats[0]
+		r.slowest = r.lats[len(r.lats)-1]
+		fmt.Printf("\nSummary:\n")
+		fmt.Printf("  Total:\t%4.4f secs.\n", r.total.Seconds())
+		fmt.Printf("  Slowest:\t%4.4f secs.\n", r.slowest)
+		fmt.Printf("  Fastest:\t%4.4f secs.\n", r.fastest)
+		fmt.Printf("  Average:\t%4.4f secs.\n", r.average)
+		fmt.Printf("  Requests/sec:\t%4.4f\n", r.rps)
+		r.printHistogram()
+		r.printLatencies()
+	}
+
+	if len(r.errorDist) > 0 {
+		r.printErrors()
+	}
+}
+
+// Prints percentile latencies.
+func (r *report) printLatencies() {
+	pctls := []int{10, 25, 50, 75, 90, 95, 99}
+	data := make([]float64, len(pctls))
+	j := 0
+	for i := 0; i < len(r.lats) && j < len(pctls); i++ {
+		current := i * 100 / len(r.lats)
+		if current >= pctls[j] {
+			data[j] = r.lats[i]
+			j++
+		}
+	}
+	fmt.Printf("\nLatency distribution:\n")
+	for i := 0; i < len(pctls); i++ {
+		if data[i] > 0 {
+			fmt.Printf("  %v%% in %4.4f secs.\n", pctls[i], data[i])
+		}
+	}
+}
+
+func (r *report) printHistogram() {
+	bc := 10
+	buckets := make([]float64, bc+1)
+	counts := make([]int, bc+1)
+	bs := (r.slowest - r.fastest) / float64(bc)
+	for i := 0; i < bc; i++ {
+		buckets[i] = r.fastest + bs*float64(i)
+	}
+	buckets[bc] = r.slowest
+	var bi int
+	var max int
+	for i := 0; i < len(r.lats); {
+		if r.lats[i] <= buckets[bi] {
+			i++
+			counts[bi]++
+			if max < counts[bi] {
+				max = counts[bi]
+			}
+		} else if bi < len(buckets)-1 {
+			bi++
+		}
+	}
+	fmt.Printf("\nResponse time histogram:\n")
+	for i := 0; i < len(buckets); i++ {
+		// Normalize bar lengths.
+		var barLen int
+		if max > 0 {
+			barLen = counts[i] * 40 / max
+		}
+		fmt.Printf("  %4.3f [%v]\t|%v\n", buckets[i], counts[i], strings.Repeat(barChar, barLen))
+	}
+}
+
+func (r *report) printErrors() {
+	fmt.Printf("\nError distribution:\n")
+	for err, num := range r.errorDist {
+		fmt.Printf("  [%d]\t%s\n", num, err)
+	}
+}