How to change process priority

Question

Level 1

32 points

How to change process priority

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)

Posted on Apr 19, 2008 10:24 AM

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Answer 1

Top-ranking reply

carillonator

Level 1

13 points

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.

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Answer 2

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?

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Answer 3

Chris CA

Level 10

82,513 points

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.

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Answer 4

JeffCMKRNL Author

Level 1

32 points

Apr 19, 2008 5:03 PM in response to BDAqua

That looks like what I am looking for.
I tried it but I could not get it to work. I think it is because of the "utility" argument. At first I used the path to the handbrake application. This is what I tried and the error I received:
Arakis:~ jeff$ nice 10 /Applications/HandBrake/HandBrake.app
nice: 10: No such file or directory
What is meant by the "utility" argument?

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Answer 5

JeffCMKRNL Author

Level 1

32 points

Apr 21, 2008 1:02 PM in response to BDAqua

That is exactly how I did it. I did have a space after the 10, and I dragged the application to the terminal window, and it responded with the "Not found" error message.

I will try the renice when I get home tonight. At work I am using Windows 2000 and Lotus notes (AAAArrrrgh!). I also support 4 PDP-11s and 6 antique VAX systems and an old Stratus.

I have renamed the title of my position to "Paleocybernetic Systems Administrator".

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Answer 6

JeffCMKRNL Author

Level 1

32 points

Apr 22, 2008 2:01 PM in response to polyglotinc

Well, I think it worked, but I'm not seeing the processing being registered as "nice" cpu usage, so I am not sure.

I could not find a way in the activity monitor to display process priority. Is there a way to view the current priority either in Activity Monitor, or in Terminal?

Jeff

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Answer 7

BDAqua

Level 10

250,253 points

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. 🙂

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Answer 8

BDAqua

Level 10

250,253 points

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.

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