High CPU usage, Mouse non smooth

[giuliocoluccia]

Hi,
I'm running ubuntu 14.04.3 with latest kernel & Xorg:
giulio@caratinga:~$ uname -r
3.19.0-37-generic
giulio@caratinga:~$ X -version

X.Org X Server 1.17.1
Release Date: 2015-02-10
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.19.0-28-generic x86_64 Ubuntu
Current Operating System: Linux caratinga 3.19.0-37-generic #42~14.04.1-Ubuntu SMP Mon Nov 23 15:13:51 UTC 2015 x86_64
Kernel command line: BOOT_IMAGE=/vmlinuz-3.19.0-37-generic root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
Build Date: 11 September 2015 10:33:14AM
xorg-server 2:1.17.1-0ubuntu3.1~trusty1 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.30.2
Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.


I'm experiencing the following issues. I have a DVI monitor plugged to a USB 3.0 docking station, which I use as my only monitor (the laptop lid is closed). The first is the high CPU usage of /usr/lib/displaylink/DisplayLinkManager which ranges from 20 to 60 percent (problem disappears if I unplug the dock). The second is the mouse movement which is not smooth on the external monitor, but it is on the integrated display and also on the same monitor when plugged to the mini DisplayPort.

I attach the result of the Linux Support Tool.

Thank you

[giuliocoluccia]

I see that there's a new driver coming out, but for the moment it gives me a blank page telling me that the access is denied (see attachment). I'll try again and test it when available.

[giuliocoluccia]

Nothing seems to be changed with this new release. Still having high CPU usage from DisplayLinkManager (see attachment) processes and mouse movement still non smooth.

[jack_kelly]

I also see high CPU usage from DisplayLinkManager

(I'm on Ubuntu 15.10 using the latest DisplayLink driver and a USB3 to DisplayPort adapter)

[giuliocoluccia]

Same here, but nobody from DisplayLink seems to reply..

[mlukaszek]

Standard Ubuntu's graphical environment, Unity, causes the screen to be always reported as modified full screen, regardless of which screen changes.

That means: even if nothing changes on the screen which is connected to a docking station, we are still told by the OS to resend full screen update if anything is happening on other screen (e.g. built-in laptop screen).

This gets better in other environments - Gnome3 or KDE for example. I would be interested to see if you experience the same CPU usage if you try other env.

Thanks,
Michal

[jack_kelly]

ah, interesting, thanks for the quick reply :)

[giuliocoluccia]

Standard Ubuntu's graphical environment, Unity, causes the screen to be always reported as modified full screen, regardless of which screen changes.

That means: even if nothing changes on the screen which is connected to a docking station, we are still told by the OS to resend full screen update if anything is happening on other screen (e.g. built-in laptop screen).

This gets better in other environments - Gnome3 or KDE for example. I would be interested to see if you experience the same CPU usage if you try other env.

Thanks,
Michal

I actually use Unity and I'd prefer not to change the environment. But my standard usage is to close the lid of the laptop, hence it is off. I use *only* the monitor attached to the docking station 99% of the time.

[mlukaszek]

my standard usage is to close the lid of the laptop, hence it is off. I use *only* the monitor attached to the docking station 99% of the time.

Which I think sometimes can make things even worse. Lid close multi-monitor scenarios in Linux are something that still need more love - but this varies across GPUs and distros. What is your setup?

Thanks,
Michal

[giuliocoluccia]

Ubuntu 14.04.3 (Unity), Intel HD Graphics 4000 GPU (driver i915)

$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)


No problem at all with same setup/usage, but external monitor attached to mini DisplayPort

[giuliocoluccia]

Standard Ubuntu's graphical environment, Unity, causes the screen to be always reported as modified full screen, regardless of which screen changes.

That means: even if nothing changes on the screen which is connected to a docking station, we are still told by the OS to resend full screen update if anything is happening on other screen (e.g. built-in laptop screen).

This gets better in other environments - Gnome3 or KDE for example. I would be interested to see if you experience the same CPU usage if you try other env.

Thanks,
Michal
Maybe this is a stupid question: if the problem is Unity reporting a full refresh, why doesn't the same issue appear when the same external monitor is connected directly to the mini displayport using a miniDP2DVI adapter?