A small benchmark testing the toll of converting a block to a Proc object.

block_objects_speed.rb

# With Ruby 2.1.0-preview1 this benchmark outputs:
#
#                             user     system      total        real
# calling_with_param       1.450000   0.150000   1.600000 (  1.874802)
# calling_with_proc_new    0.920000   0.060000   0.980000 (  1.004593)
# calling_with_yield       0.220000   0.000000   0.220000 (  0.233624)
# returning_with_param     1.300000   0.080000   1.380000 (  1.414610)
# returning_with_proc_new  0.830000   0.040000   0.870000 (  0.880629)

require 'benchmark'

def calling_with_param(needs_proc_object, &blk)
  if needs_proc_object
    blk.call
  else
    yield
  end
end

def calling_with_proc_new(needs_proc_object)
  if needs_proc_object
    Proc.new.call
  else
    yield
  end
end

def calling_with_yield(needs_proc_object)
  yield
end

def returning_with_param(needs_proc_object, &blk)
  blk if needs_proc_object
end

def returning_with_proc_new(needs_proc_object)
  Proc.new if needs_proc_object
end

runs = 1_000_000

Benchmark.bm do |bm|
  bm.report('calling_with_param     ') { runs.times { |run| calling_with_param(run.even?) {}      } }
  bm.report('calling_with_proc_new  ') { runs.times { |run| calling_with_proc_new(run.even?) {}   } }
  bm.report('calling_with_yield     ') { runs.times { |run| calling_with_yield(run.even?) {}      } }
  bm.report('returning_with_param   ') { runs.times { |run| returning_with_param(run.even?) {}    } }
  bm.report('returning_with_proc_new') { runs.times { |run| returning_with_proc_new(run.even?) {} } }
end