#!/bin/bash
# Runs ApacheBench a preset number of times and outputs the mean request time as CSV
#
# Bryant Casteel
# http://bethings.postplatinum.com/tag/ab-time-chart/
# 2010-12-05

# configuration

MIN_CONNECTIONS=1
MAX_CONNECTIONS=400
SAMPLES=100

# output the column headings
echo -n '""'
for url in $*; do
  echo -n ',"'"$url"'"'
done
echo

# output row of zeroes for origin
echo -n '0'
for url in $*; do
  echo -n ',0'
done
echo

# for increasing number of concurrent connections
interval=1
connections=$MIN_CONNECTIONS
while (( connections <= MAX_CONNECTIONS )); do
  # output the row heading
  echo -n "$connections"

  # test each URL
  (( hits = ( connections * SAMPLES ) ))
  for url in $*; do
    mean_time=`ab -n $hits -c $connections "$url" | grep 'Time per request.*(mean)' \
      | cut -c25- | sed 's/^\([0-9\.]\+\).*$/\1/'`
    echo -n ",$mean_time"
  done

  # end the row
  echo

  # calculate next increment
  if (( ( connections / (interval * 10) ) >= 1 )); then
    # increment the connections by increasing powers of 10
    (( interval = (interval * 10) ))
  fi
  (( connections = ( connections + interval) ))
done