File.exist? benchmark of existing / non existing file

gistfile1.txt

ubuntu@localtest:~$ cat stat.rb 
require 'benchmark'

puts Benchmark.measure { 
  1000000.times do
    File.exist?(ARGV[0])
  end
}
ubuntu@localtest:~$ ls -l foo
ls: cannot access foo: No such file or directory
ubuntu@localtest:~$ ruby stat.rb foo
  0.570000   0.310000   0.880000 (  0.876064)
ubuntu@localtest:~$ ruby stat.rb stat.rb
  0.560000   0.390000   0.950000 (  0.952491)