vendor/rails/railties/doc/guides/source/benchmarking_and_profiling/edge_rails_features.txt

   1 == Performance Testing Built into Rails ==
   2
   3 As of June 20, 2008 edge rails has had a new type of Unit test geared towards profiling. Of course like most great things, getting it working takes  bit of work. The test relies on statistics gathered from the Garbage Collection that isn't readily available from standard compiled ruby. There is a patch located at http://rubyforge.org/tracker/download.php/1814/7062/17676/3291/ruby186gc.patch[http://rubyforge.org/tracker/download.php/1814/7062/17676/3291/ruby186gc.patch]
   4
   5 Also the test requires a new version of Ruby-Prof version of 0.6.1. It is not readily available at the moment and can most easily be found as a tarball on github. It's repository is located at git://github.com/jeremy/ruby-prof.git.
   6
   7 What follows is a description of how to set up an alternative ruby install to use these features
   8
   9 === Compiling the Interpreter ===
  10
  11
  12 [source, shell]
  13 ----------------------------------------------------------------------------
  14 [User ~]$ mkdir rubygc
  15 [User ~]$ wget ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.6-p111.tar.gz
  16 [User ~]$ tar -xzvf ruby-1.8.6-p111.tar.gz
  17 [User ~]$ cd ruby-1.8.6-p111
  18 [User ruby-1.8.6-p111]$ curl http://rubyforge.org/tracker/download.php/1814/7062/17676/3291/ruby186gc.patch | patch -p0
  19
  20 #I like putting my alternative ruby builds in an opt directory, set the prefix to where ever you feel is most comfortable.
  21
  22 [User ruby-1.8.6-p111]$ ./configure --prefix=/opt/rubygc
  23 [User ruby-1.8.6-p111]$ sudo make && make install
  24 ----------------------------------------------------------------------------
  25
  26 Add the following lines in your \~/.profile or \~/.bash\_login for convenience.
  27
  28 ----------------------------------------------------------------------------
  29 alias gcruby='/opt/rubygc/rubygc/bin/ruby'
  30 alias gcrake='/opt/rubygc/rubygc/bin/rake'
  31 alias gcgem='/opt/rubygc/rubygc/bin/gem'
  32 alias gcirb=/opt/rubygc/rubygc/bin/irb'
  33 alias gcrails='/opt/rubygc/rubygc/bin/rails'
  34 ----------------------------------------------------------------------------
  35
  36 === Installing RubyGems ===
  37
  38 Next we need to install rubygems and rails so that we can use the interpreter properly.
  39
  40
  41 [source, shell]
  42 ----------------------------------------------------------------------------
  43 [User ~]$ wget http://rubyforge.org/frs/download.php/38646/rubygems-1.2.0.tgz
  44 [User ~]$ tar -xzvf rubygems-1.2.0.tgz
  45 [User ~]$ cd rubygems-1.2.0
  46 [User rubygems-1.2.0]$ gcruby setup.rb
  47 [User rubygems-1.2.0]$ cd ~
  48 [User ~]$ gcgem install rake
  49 [User ~]$ gcgem install mysql
  50 [User ~]$ gcgem install rails
  51 ----------------------------------------------------------------------------
  52
  53 If installing mysql gem fails ( like it did for me ), you will have to manually install it :
  54
  55 [source, shell]
  56 ----------------------------------------------------------------------------
  57 [User ~]$ cd /Users/lifo/rubygc/lib/ruby/gems/1.8/gems/mysql-2.7/
  58 [User mysql-2.7]$ gcruby extconf.rb --with-mysql-config
  59 [User mysql-2.7]$ make && make install
  60 ----------------------------------------------------------------------------
  61
  62 === Installing Jeremy Kemper's ruby-prof ===
  63
  64 We are in the home stretch. All we need now is ruby-proff 0.6.1
  65
  66
  67 [source, shell]
  68 ----------------------------------------------------------------------------
  69 [User ~]$ git clone git://github.com/jeremy/ruby-prof.git
  70 [User ~]$ cd ruby-prof/
  71 [User ruby-prof (master)]$ gcrake gem
  72 [User ruby-prof (master)]$ gcgem install pkg/ruby-prof-0.6.1.gem
  73 ----------------------------------------------------------------------------
  74
  75 Finished, go get yourself a power drink!
  76
  77 === Ok so I lied, a few more things we need to do ===
  78
  79 You have everything we need to start profiling through rails Unit Testing. Unfortunately we are still missing a few files. I'm going to do the next step on a fresh Rails app, but it will work just as well on developmental 2.1 rails application.
  80
  81 ==== The Rails App ====
  82
  83 First I need to generate a rail app
  84
  85 [source, shell]
  86 ----------------------------------------------------------------------------
  87 [User ~]$ gcrails profiling_tester -d mysql
  88 [User ~]$ cd profiling_tester
  89 [User profiling_tester]$ script/generate scaffold item name:string
  90 [User profiling_tester]$ gcrake db:create:all
  91 [User profiling_tester]$ gcrake db:migrate
  92 [User profiling_tester (master)]$ rm public/index.html
  93 ----------------------------------------------------------------------------
  94
  95 Now I'm going to init it as a git repository and add edge rails as a submodule to it.
  96
  97 [source, shell]
  98 ----------------------------------------------------------------------------
  99 [User profiling_tester]$ git init
 100 [User profiling_tester (master)]$ git submodule add git://github.com/rails/rails.git vendor/rails
 101 ----------------------------------------------------------------------------
 102
 103 Finally we want to  change config.cache_classes to true in our environment.rb
 104
 105 ----------------------------------------------------------------------------
 106 config.cache_classes = true
 107 ----------------------------------------------------------------------------
 108
 109 If we don't cache classes, then the time Rails spends reloading and compiling our models and controllers will confound our results.  Obviously we will try to make our test setup as similar as possible to our production environment.
 110
 111 === Generating and Fixing the tests ===
 112
 113 Ok next we need to generate the test script.
 114
 115 [source, shell]
 116 ----------------------------------------------------------------------------
 117 [User profiling_tester (master)]$ script/generate performance_test homepage
 118 ----------------------------------------------------------------------------
 119
 120 This will generate _test/performance/homepage_test.rb_ for you. However, as I have generated the project using Rails 2.1 gem, we'll need to manually generate one more file before we can go ahead.
 121
 122 We need to put the following inside _test/performance/test_helper.rb
 123
 124
 125 [source, ruby]
 126 ----------------------------------------------------------------------------
 127 require 'test_helper'
 128 require 'performance_test_help'
 129 ----------------------------------------------------------------------------
 130
 131 Though this depends where you run your tests from and your system config. I myself run my tests from the Application root directory
 132
 133 so instead of
 134
 135 [source, ruby]
 136 ----------------------------------------------------------------------------
 137 require 'test_helper'
 138
 139 #I have
 140
 141 require 'test/test_helper'
 142 ----------------------------------------------------------------------------
 143
 144 Also I needed to change homepage_test.rb to reflect this also
 145
 146 [source, ruby]
 147 ----------------------------------------------------------------------------
 148 require 'test/performance/test_helper.rb'
 149 ----------------------------------------------------------------------------
 150
 151 === Testing ===
 152
 153 #TODO is there some way to compare multiple request at once like ruby_analyze
 154
 155 Now, if we look at the generated performance test ( one we generated using _script/generate performance_test_ ), it'll look something like :
 156
 157 [source, ruby]
 158 ----------------------------------------------------------------------------
 159 .require 'performance/test_helper'
 160
 161 class HomepageTest < ActionController::PerformanceTest
 162   # Replace this with your real tests.
 163   def test_homepage
 164     get '/'
 165   end
 166 end
 167 ----------------------------------------------------------------------------
 168
 169
 170 The format looks very similar to that of an integration test. And guess what, that's what it is. But that doesn't stop you from testing your Model methods. You could very well write something like :
 171
 172 [source, ruby]
 173 ----------------------------------------------------------------------------
 174 require 'performance/test_helper'
 175
 176 class UserModelTest < ActionController::PerformanceTest
 177   # Replace this with your real tests.
 178   def test_slow_find
 179     User.this_takes_shlong_to_run
 180   end
 181 end
 182 ----------------------------------------------------------------------------
 183
 184
 185 Which is very useful way to profile individual processes.