Disable GC and running the collector manually every few seconds for cuke runs

deferred_gc.rb

# Taken from Jamis Buck's post "The road to faster tests"
# http://37signals.com/svn/posts/2742-the-road-to-faster-tests
#
# Disabling GC and running the collector manually every few seconds
# knocks 25-30% off the time taken to run all of my non-js scenarios
# on ruby 1.9.3p448, without any other memory management tuning.

DEFERRED_GC_THRESHOLD = (ENV['CUCUMBER_DEFERRED_GC_THRESHOLD'] || 3.0).to_f

last_gc_run = Time.now

Before do
  GC.disable if DEFERRED_GC_THRESHOLD > 0
end

After do
  if DEFERRED_GC_THRESHOLD > 0 && Time.now - last_gc_run >= DEFERRED_GC_THRESHOLD
    GC.enable
    GC.start
    last_gc_run = Time.now
  end
end