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How to change process priority

32824 Views 8 Replies Latest reply: Apr 22, 2008 2:01 PM by JeffCMKRNL RSS
JeffCMKRNL Level 1 Level 1 (10 points)
Currently Being Moderated
Apr 19, 2008 10:24 AM
How can I change the cpu priority of a process?
I could not find a way to do this using the Activity Monitor. How about a command using the terminal app?
When I am using Handbrake, I would like to lower its process priority to compute in the background.

Thank you in advance.
Dual PowerMAC G5, G5 Mac Mini, CoreDuo MacBook, Mac OS X (10.4.9)
  • BDAqua Level 10 Level 10 (114,790 points)
    Currently Being Moderated
    Apr 19, 2008 1:11 PM (in response to JeffCMKRNL)
    Hi Jeff,

    Just do a...

    man nice

    in Terminal, and note how it's backwards... minus is faster, plus is slower.
  • BDAqua Level 10 Level 10 (114,790 points)
    Currently Being Moderated
    Apr 19, 2008 5:34 PM (in response to JeffCMKRNL)
    Just type that nice 10 with a space after it, then drag handbrake from a finder window to the Terminal window... see if that works better.
  • carillonator Calculating status...
    Currently Being Moderated
    Apr 20, 2008 8:50 PM (in response to JeffCMKRNL)
    you have to refer to the process by its ID. Go to the Activity Monitor (Apps>Utilities) and find handbrake and its ID. Use renice to re-prioritize an already-running process--nice is to start the process from the terminal.

    To set it to its lowest priority:

    sudo renice 20 2933

    where 2933 is the process' ID (change it to yours). 0 priority is default, -20 is highest.
    MacBook Pro 2.2, Mac OS X (10.5)
  • Chris CA Level 9 Level 9 (73,410 points)
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    Apr 20, 2008 9:03 PM (in response to JeffCMKRNL)
    This -> Renicer seems to work okay. I haven't had any problems with 10.4.11.
    iMac G5 (Rev B) ALS - 1 GB RAM, Mac OS X (10.4.11), silver mini, blue mini, silver shuffle
  • polyglotinc Calculating status...
    Currently Being Moderated
    Apr 22, 2008 8:46 AM (in response to carillonator)
    I tried this and it did not complain with an error message but I see no evidence via Activity Monitor that it did anything!

    I am still seeing 0% Nice CPU in the CPU tab of Activity Monitor
    and Handbrake is still using 150% of CPU (I guess this is possible because of dual core CPU).

    How do we know that the renice did anything?
    iMac, Mac OS X (10.5.1)


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