Why can't I get the full processor bandwidth on my G5 Quad

[ndawes]

Hi,
Can anyone tell me how I can get more processing power applied to movie conversions with FFMPEG?

The highest processor utilization I ever get is about 214% and since I have a quad, I shoudl be able to go to almost 400%. Is there a configuration that would allow me to use this extra horsepower, or am I missing something important?
Many thanks,
nick

Powermac G5 2.5GHz Quad 4GB Ram

[DeusExMachina]

Not sure about specifics on the quad (have a 500MHZ G4, personally) but you might want to try renice-ing the application, so the OS knows to give it more processing cycles.

[ndawes]

Thanks for the advice, but how do you "re-Nice" thr program?
Many thanks,
Nick

[DeusExMachina]

Sorry it took so long to respond. Verizon networks were down all over the East Coast!

Basically, in UNIX systems, processes have degrees of priority, their "niceness" (@&*^# obfuscating UNIX geeks!!)

Nice values range from +20 through 0 into the negative. Like all things designed by @#%$ obfuscating UNIX geeks, this scale goes against intuition, such that positive numbers mean lower priority, and any negative number means top priority.
To set a nice level for ffmpeg, the first thing you need to do is run it (the encoder not the GUI) then find its PID (process ID.) This changes every time you run a process, to it will need to be reniced each time you run it. You can find the PID using Apple's free Activity Monitor that is in your Utilities folder (unless you deleted it for some reason.)
Find the ffmpeg2 process (as opposed to ffmpegX, the GUI) as well as any other related process (such as movtoy or whatever, depending on what you are doing) that may be running and record their PIDs.

Alternately, you can open terminal (you'll need that later, anyway) and type:

ps -achux

to get the list of processes.

Next, in terminal type:

sudo renice -1 PID <the PID you got from the previous step>

repeat for all processes related to the encoding (but NOT ffmpegX, since this is just the GUI and does not need prioritizing.)

Let me know if this helps at all. I am curious to know how the renice-ing works across multiple processors

[DeusExMachina]

After some research I have a bit more information for you.

To make things easier in terminal, you can use the shell program "top" to get your PIDs. Just type:
top
into terminal. After you record your PIDs, type 'q' to quit.

In order to renice more easily, try some of the GUIs here:

http://www.macupdate.com/search.php?keywords=renice&os=macosx&button.x=0&button.y=0

HTH, and let me know how it works

[DeusExMachina]

How'd that work?

[sturzi]

hi
i tried this on my dual 2ghz G5:
it doesn't make any difference, as long as the processors aren't running at 200%...
the mencoder utilizes about 120% cpu, with nice set to -1 or 20...
only when you're running another application with higher priority AND the CPUs reached 200% the processors drop the percentage spent for encoding...
well, doesn't work for this, but nice to know :P
greets