[SOLVED] Setting LXDM as default display manager for Ubuntu 15.04

273 · 08-01-2015, 03:38 AM

Quote:

Originally Posted by batabuntu

If I install Xubuntu or Lubuntu, will they use their own display manager? What I have in mind is to intall Lubuntu and install XFCE on top of it. From what I been reading online, LXDM is much lighter. I like the interface of XFCE so I want to run LXDM on XFCE, is it possible or will it break the system?

I think either Xubuntu or Lubuntu with either LXDE or XFCE will be fine -- you'll end up with pretty much the same thing if you use the same DE.
If lightdm really is showing it's using 20% of your CPU in top then I think it must be a huge bug in Ubuntu that may be worth trying to report though I admit I'm not sure of the best channels to do so. You say compiz is using 20% CPU also while this is going on? I would expect compiz to take up as much CPU as it needs but lightdm using CPU is jsut not right at all.
I am sorry if my posts sound doubtful but, really, there is something majorly wrong here if the process lightdm is using more than single-digit CPU percent whilst you are using your system. If you are seeing it using CPU in top whilst running your system something is drastically wrong.

RockDoctor · 08-01-2015, 08:15 AM

Given that you're already running XFCE, there is a simple test to see if compiz is the problem. Just install compiz (and,, I suppose, the associated emerald decorator), then switch window managers

Code:

compiz --replace

. If your cpu usage skyrockets, you've found the problem. To revert back to XFWM:

Code:

xfwm4 --replace

batabuntu · 08-02-2015, 11:03 AM

Compiz isn't the issue. It's something else.

Quote:

Originally Posted by 273

I think either Xubuntu or Lubuntu with either LXDE or XFCE will be fine -- you'll end up with pretty much the same thing if you use the same DE.
If lightdm really is showing it's using 20% of your CPU in top then I think it must be a huge bug in Ubuntu that may be worth trying to report though I admit I'm not sure of the best channels to do so. You say compiz is using 20% CPU also while this is going on? I would expect compiz to take up as much CPU as it needs but lightdm using CPU is jsut not right at all.
I am sorry if my posts sound doubtful but, really, there is something majorly wrong here if the process lightdm is using more than single-digit CPU percent whilst you are using your system. If you are seeing it using CPU in top whilst running your system something is drastically wrong.

Look at this. When I have linuxquestion.org website opened in Fireox, the CPU usage is pretty low. But when I open site like Wunderlist which might a lot of going on, the CPU usage jumps.

http://i.imgur.com/iY23rAH.png

Now I don't know what this is, is it lightdm or xorg or what else?

This is one Unity. Compiz resource was low but this was really high. The 'command' also shoots up in CPU resource when playing a video on Youtube.

I don't this exact issue when running XFCE DE on the same Ubuntu. I don't have Xubuntu installed. I'm sure lightdm runs when I'm on XFCE environment because I have that same command show in the image.

273 · 08-02-2015, 11:12 AM

The problem looks to me to be that Unity simply uses too many system resources so using anything else will lead to less CPU usage. I don't see anything to suggest that this is anything more than that.
So, the answer here is to use anything but Unity.

batabuntu · 08-03-2015, 07:47 AM

Quote:

Originally Posted by 273

The problem looks to me to be that Unity simply uses too many system resources so using anything else will lead to less CPU usage. I don't see anything to suggest that this is anything more than that.
So, the answer here is to use anything but Unity.

Thanks.

I guess even if I manage to switch to a different display manager on Unity, the issue will persist.

Going to close it.

Thanks everyone