Gathered cpu performance statistics snapshot. @attr [Fixnum] num

  The number of the cpu starting at 0 for the first cpu.

@attr [Fixnum] user

  Current counter of ticks spend in user. The counter can overflow.

@attr [Fixnum] system

  Current counter of ticks spend in system. The counter can overflow.

@attr [Fixnum] nice

  Current counter of ticks spend in nice. The counter can overflow.

@attr [Fixnum] idle

  Current counter of ticks spend in idle. The counter can overflow.