gistfile1.rbx

def gc_statistics(description = "", options = {})
    #do nothing if we don't have patched Ruby GC
    yield and return unless GC.respond_to? :enable_stats

    GC.enable_stats || GC.clear_stats
    GC.disable if options[:disable_gc]

    yield

    stat_string = description + ": "
    stat_string += "allocated: #{GC.allocated_size/1024}K total in #{GC.num_allocations} allocations, "
    stat_string += "GC calls: #{GC.collections}, "
    stat_string += "GC time: #{GC.time / 1000} msec"

    GC.log stat_string
    GC.dump if options[:show_gc_dump]

    GC.enable if options[:disable_gc]
    GC.disable_stats
end

class Hello
  def initialize
    @target = (1..100).to_a
  end
  
  def method_missing(method, *args)
    if block_given?
      @target.send(method, *args)  { |*block_args| yield(*block_args) }
    else
      @target.send(method, *args)
    end
  end
end

class World
  def initialize
    @target = (1..100).to_a
  end
  
  def method_missing(method, *args, &block)
    if block_given?
      @target.send(method, *args, &block)
    else
      @target.send(method, *args)
    end
  end
end

h = Hello.new
w = World.new

gc_statistics("Without Block map") { 10000.times { h.map {|x| x} } }
gc_statistics("   With Block map") { 10000.times { w.map {|x| x} } }

gc_statistics("Without Block min") { 10000.times { h.min } }
gc_statistics("   With Block min") { 10000.times { w.min } }

Results

Without Block map: allocated: 11992K total in 2040004 allocations, GC calls: 645, GC time: 394 msec
   With Block map: allocated: 6992K total in 90004 allocations, GC calls: 10, GC time: 17 msec
Without Block min: allocated: 78K total in 20004 allocations, GC calls: 5, GC time: 4 msec
   With Block min: allocated: 78K total in 20004 allocations, GC calls: 4, GC time: 3 msec