Goodbye...

cpu_info.rb

class CpuInfo
  def initialize
    @stats = get_cpu_stats
  end

  CPU_KEYS = %W(user nice system idle iowait irq sirq)
  LOADAVG_KEYS = %W(loadavg1 loadavg5 loadavg15)

  def stats
    res = {}

    stats = get_cpu_stats
    diff  = @stats.map.with_index { |stat, i| stats[i] - stat }
    total = diff.inject(0) { |sum, n| sum + n }
    total = 1 if total.zero?

    diff.each_with_index { |stat, i|
      res[CPU_KEYS[i]] = stat.to_f / total * 100
    }

    loadavgs = get_loadavg_stats
    loadavgs.each_with_index { |stat, i|
      res[LOADAVG_KEYS[i]] = stat
    }

    @stats = stats
    res
  end

  private

  def get_cpu_stats
    File.open("/proc/stat") { |f|
      stats = f.gets.split(' ', CPU_KEYS.size)
      stats.shift
      return stats.map { |stat| stat.to_i }
    }
  end

  def get_loadavg_stats
    File.open("/proc/loadavg") { |f|
      stats = f.gets.split(' ', LOADAVG_KEYS.size)
      return stats.map { |stat| stat.to_f }
    }
  end
end