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Let me add some context: I am currently using Ubuntu 9.10 64-bit (Desktop) on a relatively powerful stationary PC (Intel Core i7 920, 12GB ram). My purpose is highspeed imaging with a pointgrey Grashopper machine-vision camera (for research, PhD project). This camera is capable of 200 fps at full VGA (640x480) resolution. The camera is connected using Firewire (1394b) and the drivers and software from Pointgrey works great. I have developed a console C++ application that can grap a certain number of frames to preallocated memory and after this also save the grapped frames to harddrive. Currently it works fine but sometimes I am observing a few framedrops (1-3). When this happens I reset the experiment and repeat the recording and usually i am lucky the second time with no framedrops (the camera-driver has a internal framecounter that I am using).

Question: I usually go to tty1 and use "sudo service gdm stop" to disable the graphical frontend. It seems to release some memory though that is not my main concern. My concern is CPU resources. Are there other system hungry modules that can be disabled temporarily such that the CPU gets less busy on Ubuntu 9.10?

At some point in the future I will update to 10.10. Should I perhaps option for the server edition instead?


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Depending on how long the experiment is you could temporarily hold back the other processes with cpulimit. You might have to experiment a bit to find out who the big users are before putting the brakes on them. The good thing is that once you have finished you can stop cpulimit and everything will be back to normal. One thing to mention you will have to do a bit of math as you have a quad core to take into account the %per core not difficult but it will make a difference to the result.

Hope this helps.

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Thanks. I will take a look at it next week. – Ole Thomsen Buus Jan 30 '11 at 15:45
Hi again. I took a look at cpulimit and though I have not tried that tool yet, I was perhaps more looking for clues into certain processes that run by default and which are already know to be "big users". For instance, I do not need network access when I use the camera. I do need 1394b, USB, monitor, and filesystem access. But that's about it. – Ole Thomsen Buus Feb 2 '11 at 10:41
Is the desktop completely necessary? because if you could log in to a terminal instead of the desktop that will significantly reduce cpu usage as one of the "big users" is X-org. I would suggest making a bash script of the commands you would need to run so you can call it and save a lot of typing. – Allan Feb 2 '11 at 11:42
@Allan The desktop is not necessary. That is also why I go to tty1 and stop the gdm service (as far as I understand, I am no linux expert at all - normally use windows). But how do you mean exactly - "log on to a terminal" ? Is that not what I am doing by using ctrl+alt+F1 and go to tty1? – Ole Thomsen Buus Feb 6 '11 at 12:18
What I was going to suggest is at the login screen below where you enter your password there should be a drop down to select which session you want if you choose "recovery console" you get a terminal session without all of that gnome nautilus etc... processes to worry about. – Allan Feb 6 '11 at 13:16

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