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top, by default, lists both columns. I am curious as to what is the difference. I checked out the man pages and cannot figure it out:


   h: PR  --  Priority
      The priority of the task.

Nice value:

   i: NI  --  Nice value
      The nice value of the task.  A negative nice value means higher  priority,
      whereas  a  positive  nice value means lower priority.  Zero in this field
      simply means priority will not be adjusted in determining  a  task’s  dis-

I understand that Nice value is related to the Kernel's CPU scheduler queue; then what does Priority indicate? Something regarding I/O perhaps?

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1 Answer 1

up vote 4 down vote accepted

The nice value is a "global" mechanism, whereas priority is relevant for the task switcher right now.

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What do you mean by task switcher? –  Belmin Fernandez Oct 27 '10 at 0:21
The task switcher (properly called the "scheduler") is a little bit of code within the kernel that decides what task will run next. –  Ignacio Vazquez-Abrams Oct 27 '10 at 4:12
As always, thanks Ignacio! –  Belmin Fernandez Oct 27 '10 at 14:47

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