Graphing ApacheBench Results Using GnuPlot

Ab / ApacheBench is a tool commonly used to perform benchmark by many people. unfortunately, the results are displayed somewhat difficult to read by most people. but it can be tricked by turning it into a plot image. this time, I will make examples how to change the results of apachebench into a form of image plots using gnuplot. although apachebench’s report is very helpful, we need to output the data in a parse-able format. To do this we use the -g switch which will output a gnuplot-friendly tab delimited table of data.

First we need to installed gnuplot if we don’t have it yet.

$sudo yum -y install gnuplot

In this example i’ll benchmark request on static png file.

Run first webserver benchmark

$ ab -k -n 50000 -c 100 -g server1.txt http://server1/server1.png

Run second webserver benchmark

$ ab -k -n 50000 -c 100 -g server2.txt http://server2/server2.png

Example result server1.txt/server2.txt

starttime       seconds ctime   dtime   ttime   wait
Tue May 10 16:42:28 2011        1305020548      0       2       2       2
Tue May 10 16:42:28 2011        1305020548      0       2       2       2
Tue May 10 16:42:28 2011        1305020548      0       3       3       2
Tue May 10 16:42:28 2011        1305020548      0       3       3       3
Tue May 10 16:42:28 2011        1305020548      0       3       3       3
Tue May 10 16:42:28 2011        1305020548      0       3       3       3
Tue May 10 16:42:28 2011        1305020548      0       3       3       3
Tue May 10 16:42:28 2011        1305020548      0       3       3       3

Now we’ll convert tab delimited tables datas into a nice image plot

Create plot template file called template.p, so it can be re-used easily for later test.

# output as png image
set terminal png

# save file to "benchmark.png"
set output "benchmark.png"

# graph a title
set title "ab -k -n 50000 -c 100"

# nicer aspect ratio for image size
set size 1,0.7

# y-axis grid
set grid y

# x-axis label
set xlabel "request"

# y-axis label
set ylabel "response time (ms)"

# plot data from "server1.txt" and "server2.txt" using column 9 with smooth sbezier lines
plot "server1.txt" using 9 smooth sbezier with lines title "server1:", \
     "server2.txt" using 9 smooth sbezier with lines title "server2:"

Run gnuplot to generate graph

$ gnuplot template.p

Here’s an example of gnuplot graph