def usage(interval = 1, &block)
      unless @usage
        if processor = CPU.usage(interval, &block).find {
          |p| p.processor_id == processor_id
        }
        then
          @usage = processor.usage
        end
      end
      @usage
    end
def usage(interval = 1, &block)
      unless @usage
        if processor = CPU.usage(interval, &block).find {
          |p| p.processor_id == processor_id
        }
        then
          @usage = processor.usage
        end
      end
      @usage
    end
Measure CPU usage for this Processor instance during the next +interval+
 or during the runtime of the given block. Іf CPU usage on all processors
 of the system should be measured, it's better (=faster) to use the
 CPU.usage method instead.