Unity is sluggish and uses a lot of CPU (even with hardware support) on low-end systems

Bug #1067349 reported by Benjamin Schmid on 2012-10-16
This bug affects 16 people
Affects Status Importance Assigned to Milestone
unity (Ubuntu)

Bug Description

I asked this question already on Askubuntu, but was directed to file a bug: I have a nice Lenovo Thinkpad Edge 11 AMD Neo II with a ATI Radeon 4225 integrated graphics device. In my perception this is already a not-so-lowspeced device, but still a netbook.

Up to Ubuntu 12.04 precise pangolin I preferred Unity2D over Unity mainly because it did perform much better than Unity and moreover I was able to achieve 5-6h with one battery charge. The typical load of an idling desktop settled around 0.00 to 0.02.

Yesterday I tried the new Beta 2 of Ubuntu Quantal Quetzal: This does no longer offer a Unity2D version. The performance itself has definitely improved over Unity in precise, but nevertheless I do experience now a minimum load of 0.24 to 0.36 while completely idling. According to top this is mainly due to compiz eating about 3-6% CPU all the time.

In comparison to my Unity2D experience, quantal is more sluggish, eats much faster my battery and produces significant more fan noise. I already tried a few tweaks like static blurring, fast texture renderer or choosing alternate window manager on precise, but without a significant change.

Are there ways which enable me to continue to use Ubuntu/Unity on my device without major loss of functionality, performance and battery life?
ApportVersion: 2.6.1-0ubuntu6
Architecture: i386
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,workarounds,scale,expo,ezoom]
DistroRelease: Ubuntu 12.10
MarkForUpload: True
Package: unity 6.8.0-0ubuntu2
PackageArchitecture: i386
ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7
Tags: quantal running-unity
Uname: Linux 3.5.0-18-generic i686
UpgradeStatus: Upgraded to quantal on 2012-11-06 (0 days ago)
UserGroups: adm admin audio cdrom floppy fuse kvm lpadmin netdev plugdev tape video

Omer Akram (om26er) wrote :

Something that I would love to see fixed as well.

Daniel van Vugt (vanvugt) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1055936, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.

Daniel van Vugt (vanvugt) wrote :

Hmm, actually this may not be a duplicate if you have working hardware support.

Please run this command and paste the output here:
    /usr/lib/nux/unity_support_test -p

Changed in unity:
status: New → Incomplete
Changed in unity (Ubuntu):
status: New → Incomplete
Daniel van Vugt (vanvugt) wrote :

Please also run this command to give us more information:
    apport-collect 1067349

Agree with this concern.

More attention should be given to portable devices that can't handle such loads.
One of the best things about Ubuntu a few years ago was its capacity to "resuscitate" low-specs computers. It feels it's the complete opposite now.

Bug #1069319 is related to this.

apport information

tags: added: apport-collected running-unity
description: updated

apport information

apport information

As requested I attached my output of the unity_support_test (all fine!).

Since quantal release, CPU load while fully idling has greatly improved to values below 0.05. Fan noise may partially be caused by the forced switch from fglrx to radeon with less effective power management.

X & compiz tasks stay first class cpu consumers esp. spiking on UI activity. Significant lags (3s+) remain i.e. on opening the dash obviously due to the transparency.

Daniel van Vugt (vanvugt) wrote :

Actually it's not "obviously" due to the transparency or blur at all. That's a common misconception and conclusion a lot of people jump to, even Canonical employees.

However a more detailed analysis of Unity performance shows that the main slow-down is an architectural problem. Unity and Nux are inefficient by design. And that is being worked on right now by the Unity and Nux developers. There will be a lot to look forward to in 13.04.

Good to hear lower specs are being considered at the moment, Daniel.
Do you know if some fixes will be added to pre-13.04 Ubuntu versions, or those modifications will only be for Raring as they are to heavy, i.e. affecting the backbone of Ubuntu?

Changed in unity:
status: Incomplete → Confirmed
Changed in unity (Ubuntu):
status: Incomplete → Confirmed
Daniel van Vugt (vanvugt) wrote :

The fixes don't even exist yet so I can't comment too much. However generally only small or stable and well tested fixes will get backported.

Goalie Fight (goaliefight) wrote :

I am seeing this exact same issue after upgrading from 12.04 to 12.10. Compiz and Xorg constantly uses about 5-20% even with little to no user activity and no open windows. I have Nvidia on a Dell with a i7-2720QM with 8GB RAM and the interface is very sluggish. Much slower than 12.04 which was slower than 11.10 on the same system. Let me know if I can help with uploading logs and whatnot.

summary: - After drop of Unity2D in 12.10: How to tackle high load of Unity/compiz
- on netbooks?
+ Unity is sluggish and uses a lot of CPU (even with hardware support) on
+ low-end systems
Changed in unity:
milestone: none → 7.0.0
Stephen M. Webb (bregma) on 2013-04-04
Changed in unity:
milestone: 7.0.0 → 7.0.1
Goalie Fight (goaliefight) wrote :

This issue is no longer present in 14.04.

Changed in unity:
milestone: 7.0.1 → 7.3.1
Stephen M. Webb (bregma) on 2015-02-11
Changed in unity:
milestone: 7.3.1 → 7.3.2
Stephen M. Webb (bregma) on 2015-03-19
Changed in unity:
milestone: 7.3.2 → 7.3.3
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