From: dkmd_nielsen <donn@...>
Date: 2008-10-16T05:24:42+09:00
Subject: Re: Lame question about instance variable and attribute

On Oct 15, 10:40 am, Bryan D <bdo...@gmail.com> wrote:
> On Oct 15, 7:41 am, dkmd_nielsen <d...@cmscms.com> wrote:
>
> > Assuming an attribute :field is defined, is there a processing
> > difference between using @field and self.field [within the defining
> > class?]  Does the ruby interpretter take a different path in yielding
> > the value depending how it is referenced?  I haven't notice anything.
> > I'm just curious if the interpretter takes extra steps when yielding
> > self.field.
>
> > Thanks
>
> In terms of speed, it's very close, but using @field is slightly
> faster, at least on my system.
>
> Rehearsal -----------------------------------------------
> using self:   4.640000   2.350000   6.990000 (  7.032596)
> using @:      4.550000   2.350000   6.900000 (  6.928132)
> ------------------------------------- total: 13.890000sec
>
>                   user     system      total        real
> using self:   4.660000   2.380000   7.040000 (  7.137048)
> using @:      4.570000   2.360000   6.930000 (  7.075875)
>
> Benchmark code:
> require 'benchmark'
>
> class Dummy
>   attr_reader :foo
>   def initialize
>     @foo = 7983.3435
>   end
>
>   def using_self
>     self.foo
>   end
>
>   def using_direct
>     @foo
>   end
> end
>
> n = 1000000
> @d = Dummy.new
> Benchmark.bmbm(7) do |x|
>   x.report("using self:") { n.times do @d.using_self;   end }
>   x.report("using @:")    { n.times do @d.using_direct; end }
> end

Thanks for the commentary, guys.  This is the kind of stuff that is
useful to me.  Most everything I do i very iterative.  Fortunately, if
you can call it fortunate, most of my bottlenecks have nothing to do
with Ruby.  Most of the time is I/O related stuff between servers.

Thanks again,
Happy Halloween