From f205880eab43f5faf2d6c679fdfebbb6be3329c1 Mon Sep 17 00:00:00 2001
From: "jinda.ljd" <jinda.ljd@alibaba-inc.com>
Date: Wed, 28 Jul 2021 17:47:49 +0800
Subject: [PATCH] Print the percentile of time spent on each request

---
 ab-proxy.go | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/ab-proxy.go b/ab-proxy.go
index 21e5d10..3d283db 100644
--- a/ab-proxy.go
+++ b/ab-proxy.go
@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/jessevdk/go-flags"
+	statslib "github.com/montanaflynn/stats"
 	"github.com/schollz/progressbar/v2"
 )
 
@@ -74,6 +75,17 @@ func exitWithErrorMsg(exitCode int, message string, replacements ...interface{})
 	os.Exit(exitCode)
 }
 
+type RequestCostTimeList struct {
+	statslib.Float64Data
+	locker *sync.Mutex
+}
+
+func (l *RequestCostTimeList) Insert(v float64) {
+	l.locker.Lock()
+	l.Float64Data = append(l.Float64Data, v)
+	l.locker.Unlock()
+}
+
 func main() {
 	var bar *progressbar.ProgressBar
 
@@ -174,7 +186,7 @@ func main() {
 
 	}
 
-	var stats struct {
+	var stats = struct {
 		Requests              int64
 		RequestsCompleted     int64
 		RequestsCompletedCode [1000]int64
@@ -184,7 +196,8 @@ func main() {
 		BytesTransferred      int64
 		StartTime             time.Time
 		EndTime               time.Time
-	}
+		RequestsCostData      *RequestCostTimeList
+	}{}
 
 	totalRequests := mainOpts.Bursts * mainOpts.Requests
 
@@ -232,6 +245,7 @@ func main() {
 	// start benchmarking
 
 	stats.StartTime = time.Now()
+	stats.RequestsCostData = &RequestCostTimeList{locker: new(sync.Mutex), Float64Data: statslib.Float64Data{}}
 
 	for b := 0; b < mainOpts.Bursts && stopChan != nil; b++ {
 		var requestsLeft int64
@@ -261,6 +275,7 @@ func main() {
 
 					var err error
 					var resp *http.Response
+					var startTheReq = time.Now()
 					req, err := http.NewRequest("GET", mainOpts.Args.Url, nil)
 					if err == nil {
 						req.Header = http.Header(headers)
@@ -318,19 +333,18 @@ func main() {
 
 					resp.Body.Close()
 
-
 					if errWhileReading {
 						continue
 					}
 
 					atomic.AddInt64(&stats.RequestsCompleted, 1)
+					stats.RequestsCostData.Insert(float64(time.Since(startTheReq) / time.Millisecond))
 					if resp.StatusCode >= 0 && resp.StatusCode <= 999 {
 						atomic.AddInt64(&stats.RequestsCompletedCode[resp.StatusCode], 1)
 					} else {
 						atomic.AddInt64(&stats.RequestsCompletedCode[0], 1)
 					}
 
-
 				}
 				wg.Done()
 			}()
@@ -381,6 +395,12 @@ func main() {
 		fmt.Printf("Time per request:             %s\n", timePerReq)
 	}
 
+	fmt.Println("Percentage of the requests served within a certain time (ms)")
+	for _, p := range []int{50, 75, 90, 95, 99, 100} {
+		v, _ := stats.RequestsCostData.Percentile(float64(p))
+		fmt.Printf("%3d%%\t%g\n", p, v)
+	}
+
 	if mainOpts.ShowErrors {
 		close(errChan)
 		errWg.Wait() // wait until all errors from the errChan have been set to the errMap