memrate.rb

#!/usr/bin/env ruby
## Usage: memrate.rb [-l <lib>] [-i <num>] [-t <threshold>] [-k <size>] [<host>]
## Measure memcached server read time.
## 
## Options
##   -l, --library=<lib>      Memcached client library to use. memcache-client by
##                            default. memcached also supported.
##   -i, --iterations=<num>   Number of times to read the value. If not set, read
##                            until interrupted.
##   -t, --threshold=<time>   Report iterations that take longer than <time>
##                            milliseconds to complete. Default: 20ms
##   -k, --size=<value>       Size of value to read in kilobytes. Default: 1
##
## When no <host> is specified, localhost:11211 is assumed.

# Parse options

require 'optparse'

library = 'memcache-client'
iterations = 0
threshold = 20
size = 1

ARGV.options do |o|
  o.on('-l', '--library=LIB')     { |v| library = v }
  o.on('-i', '--iterations=NUM')  { |v| iterations = v }
  o.on('-t', '--threshold=VALUE') { |v| threshold = v.to_i }
  o.on('-k', '--size=SIZE')       { |v| size = v.to_i }
  o.on('-h', '--help')            { exec "grep ^## < #$0 | cut -c4-" }
  o.parse!
end

server = ARGV[0] || 'localhost:11211'

# Choose your memcache client library

if library == 'memcache-client'
  require 'memcache'
  client = MemCache.new(server)
elsif library == 'memcached'
  require 'memcached'
  client = Memcached.new(server)
else
  fail "invalid memcache client library: #{library.inspect}"
end

# Dump config to stderr

$stderr.puts "server:     #{server}"
$stderr.puts "library:    #{library}"
$stderr.puts "threshold:  #{threshold}ms"
$stderr.puts "value size: #{size}KB"

# Genrate a key and value based on the size

key = "memrate:#{Time.now.to_f}"
value = ('0' * 1024) * size
client.set(key, value)

# Repeatedly read value from server and measure read time against
# threshold.

iteration = 0
over_threshold = 0
bailout = false
trap('INT') { puts; bailout = true }

while iterations == 0 || iteration < iterations
  iteration += 1
  start = Time.now
  client.get(key)
  time = (Time.now - start) * 1000
  if time > threshold
    over_threshold += 1
    printf "%07d %f\n", iteration, time
  end
  break if bailout
end

# Summarize

printf "total requests:   %d\n", iteration
printf "over threshold:   %d (%f%%)\n",
  over_threshold,
  (over_threshold / iteration.to_f) * 100