gistfile1.rb

# http://www.iit.edu/~kbloom1/blog/posix_fadvise.html
# http://www.lucas-nussbaum.net/blog/?p=313
# http://rubyforge.org/frs/?group_id=2338&release_id=35811

require 'rubygems'
require 'benchmark'
require 'fadvise'

string = "abcdefghijklmna"
1000.times do |n|
  File.open("#{n}", 'w') { |f| f.puts string*100 }
end

puts Benchmark.measure("file.fadvise") {
  fds = []
  1000.times do |n|
    f = File.open("#{n}", "r")
    f.fadvise 0, 2048, :no_reuse
    fds.push f
  end

  fds.each { |f|
    f.read
  }
}

puts Benchmark.measure("file.read") {
  1000.times do |n|
    f = File.open("#{n}", "r")
    f.read
  end
}