From: Phrogz <gavin@...>
Date: 2006-12-30T08:55:05+09:00
Subject: Re: Methods validating their arguments: good or bad?

Phrogz wrote:
> When the debug flag is supplied, the block is yielded and run. When
> not, the entry_check call still does have the overhead of a do-nothing
> method call, but far less than before.

Some followup performance tests from this idea:

def check; yield; end
def nothing; end

def no_test( str )
  str[ 1..3 ]
end

def test_inline( str )
  raise "OUCH" unless str.is_a?( String ) && str.length > 3
  str[ 1..3 ]
end

def test_through_block( str )
  check{
    raise "OUCH" unless str.is_a?( String ) && str.length > 3
  }
  str[ 1..3 ]
end

def dead_method_call( str )
  nothing{
    raise "OUCH" unless str.is_a?( String ) && str.length > 3
  }
  str[ 1..3 ]
end

require 'benchmark'

s = "Hello"
N = 1_000_000
Benchmark.bmbm{ |x|
  x.report( 'no_test' ){ N.times{ no_test( s ) } }
  x.report( 'dead_method_call' ){ N.times{ dead_method_call( s ) } }
  x.report( 'test_inline' ){ N.times{ test_inline( s ) } }
  x.report( 'test_through_block' ){ N.times{ test_through_block( s ) }
}
}
__END__
Rehearsal ------------------------------------------------------
no_test              2.930000   0.020000   2.950000 (  2.999768)
dead_method_call     4.030000   0.050000   4.080000 (  4.232545)
test_inline          4.830000   0.050000   4.880000 (  5.065821)
test_through_block   6.100000   0.050000   6.150000 (  6.227374)
-------------------------------------------- total: 18.060000sec

                         user     system      total        real
no_test              2.920000   0.020000   2.940000 (  2.971835)
dead_method_call     3.910000   0.030000   3.940000 (  3.990496)
test_inline          4.750000   0.040000   4.790000 (  4.825439)
test_through_block   6.140000   0.050000   6.190000 (  6.263266)