From: Alex Fenton <alex@...>
Date: 2009-02-09T07:09:15+09:00
Subject: Re: calling random

Boris Schmid wrote:
> Am I correct if I remember that using send is quite expensive in 
> cpu-time? Especially when I am using it millions of times.. $pop is 
> about 5000 hosts large.
> 
> 10000.times {
>     # Events to happen to every host this 0.1 year:
>     ["birth","death","infect","evolve"].shuffle.each {|event|

Using #send with a String argument is slower than using it with a 
Symbol. Benchmark:

-------
require 'benchmark'
class Foo
   def bar; end
end

a_foo = Foo.new

TIMES = 1_000_000

puts "Direct", Benchmark::measure { TIMES.times { a_foo.bar } }
puts "Symbol", Benchmark::measure { TIMES.times { a_foo.send(:bar) }
puts "String", Benchmark::measure { TIMES.times { a_foo.send("bar") } }
-------

With Ruby 1.8:

Direct
   0.290000   0.000000   0.290000 (  0.294786)
Symbol
   0.380000   0.000000   0.380000 (  0.385319)
String
   0.550000   0.000000   0.550000 (  0.556780)

With Ruby 1.9, the difference between #send(a_symbol) and calling the 
method directly is negligible:

Direct
   0.210000   0.000000   0.210000 (  0.209512)
Symbol
   0.210000   0.000000   0.210000 (  0.210357)
String
   0.490000   0.000000   0.490000 (  0.500568)

alex