Gave a shot to the new Bundler 1.4.0RC1 during the weekend and found out it now supports gem installation in parallel. To invoke you need to pass --jobs parameter with number of threads you want it to run – for me the best performance was achieved by specifying the number physical CPU cores.

I've tested on the AppFab app. In my case (CPU with 2-core i7 with HT) the speedup was 50%. I've also tried with a number greater than the number of physical cores but the performance was 15%-20% worse.

Bundler 1.3...

This method won't throw an error:

def a_method
  raise
ensure
  return :something
end

it will in fact return :something

So please proceed with care :)

require 'ruby-prof' # you don't need this if you have ruby-prof in your Gemfile

You can set one of the things you want to measure by using (default is PROCESS_TIME most useful ones are PROCESS_TIME, MEMORY, CPU_TIME):
RubyProf.measure_mode = RubyProf::PROCESS_TIME
RubyProf.measure_mode = RubyProf::WALL_TIME
RubyProf.measure_mode = RubyProf::CPU_TIME
RubyProf.measure_mode = RubyProf::ALLOCATIONS
RubyProf.measure_mode = RubyProf::MEMORY
RubyProf.measure_mode = RubyProf::GC_RUNS
RubyProf.measure_mode = ...

One of the main source of bugs and complexity in the code is when a functional method (that we expect to return a value) return different values under different circumstances.

For example, we ruby programmers have a bad habit of returning nil from a method when certain condition is not fulfilled else return an Array or Hash. That just makes the calling code unnecessary complex and error prone because then it has to do different checks.

Bad Practice:

def bad_method(param)
  return unless param == 'something'
  [1,2,3]
end

...

Go to lib folder and use bundler to generate main files for a gem:

$ bundle gem test_gem

      create  test_gem/Gemfile
      create  test_gem/Rakefile
      create  test_gem/LICENSE
      create  test_gem/README.md
      create  test_gem/.gitignore
      create  test_gem/test_gem.gemspec
      create  test_gem/lib/test_gem.rb
      create  test_gem/lib/test_gem/version.rb
Initializating git repo in /path/to/webapp/HouseTrip-Web-App/lib/test_gem

cd in to created directory

$ cd test_gem/

Bundle...