为什么在顶部突出显示某些过程？

为什么在顶部突出显示某些过程？高亮有特殊含义吗？谢谢！

要扩展道格的答案，请查看过程的状态。除了三个突出显示的过程之外，所有过程都处于状态S，并且三个突出显示的过程都处于状态R。在top联机帮助页的第20条第3a节中给出了过程状态：

20. S  --  Process Status
   The status of the task which can be one of:
       D = uninterruptible sleep
       R = running
       S = sleeping
       T = traced or stopped
       Z = zombie

   Tasks  shown  as running should be more properly thought of as
   'ready to run'  --  their task_struct is simply represented on
   the Linux run-queue.  Even without a true SMP machine, you may
   see numerous tasks in this  state  depending  on  top's  delay
   interval and nice value.

要切换该突出显示，请按y：

y :Row-Highlight toggle
  Changes highlighting for "running" tasks.   For  additional
  insight into this task state, see topic 3a. DESCRIPTIONS of
  Fields, the 'S' field (Process Status).

  Use of this provision provides important insight into  your
  system's  health.   The only costs will be a few additional
  tty escape sequences.

突出显示的3个进程是3个正在运行的进程。