From: Robert Dober <robert.dober@...>
Date: 2007-03-03T03:53:07+09:00
Subject: Re: default passed block for method

On 3/2/07, Rick DeNatale <rick.denatale@gmail.com> wrote:
> Just for giggles, I combined Robert and Joel's benchmarks and ran them
> on both ruby 1.8 and a quite recent 1.9.  Perhaps the results are of
> interest.
>
> rick@frodo:/public/rubyscripts$ ruby1.8 blkgiven.rb
> Rehearsal -----------------------------------------------------
> rd - block_given?   6.070000   1.620000   7.690000 ( 15.323920)
> jv - block_given?   3.530000   0.530000   4.060000 (  9.952521)
> rd - &blk          29.620000   2.090000  31.710000 ( 55.018634)
> jv - &blk           8.580000   1.400000   9.980000 ( 13.505903)
> ------------------------------------------- total: 53.440000sec
>
>                         user     system      total        real
> rd - block_given?   6.430000   1.550000   7.980000 ( 12.312925)
> jv - block_given?   3.470000   0.630000   4.100000 (  7.956797)
> rd - &blk          28.920000   2.040000  30.960000 ( 55.456023)
> jv - &blk           8.860000   1.350000  10.210000 ( 12.264554)
>
>
> rick@frodo:/public/rubyscripts$ ruby1.9 blkgiven.rb
> Rehearsal -----------------------------------------------------
> rd - block_given?   1.950000   0.000000   1.950000 (  2.503581)
> jv - block_given?   1.930000   0.010000   1.940000 (  3.029174)
> rd - &blk          10.870000   0.020000  10.890000 ( 21.230573)
> jv - &blk           2.430000   0.000000   2.430000 (  6.296742)
> ------------------------------------------- total: 17.210000sec
>
>                         user     system      total        real
> rd - block_given?   2.040000   0.010000   2.050000 (  3.862906)
> jv - block_given?   1.770000   0.000000   1.770000 (  2.239562)
> rd - &blk          10.520000   0.050000  10.570000 ( 17.941764)
> jv - &blk           2.450000   0.010000   2.460000 (  3.961397)
> rick@frodo:/public/rubyscripts$
> ---
> Rick DeNatale
>
> My blog on Ruby
> http://talklikeaduck.denhaven2.com/
>
>

Rick I think as a matter of fact that both benchmarks are important.
I was too humble, but that will not happen again ;)

Let us look at Jo�l's first, it applies to the following pattern:

def method &blk
    blk ||= proc{true}
   MANY.times do
        ...
       blk.call
       ...
  end
end

from the performance POV you can get away with it.
==================================================
my naive benchmark was benchmarking the following pattern - which
exits quite often too.

def method &blk
    blk ||= proc{ true }
   ...
   blk.call
   ...
end

Now of course the proc is a killer as we have as many proces as #call :(

Hopefully this kind of a reasonable conclusion about the performance
cost of the whole stuff.

Cheers
Robert

-- 
We have not succeeded in answering all of our questions.
In fact, in some ways, we are more confused than ever.
But we feel we are confused on a higher level and about more important things.
-Anonymous