unity-panel-service cause high cpu usage during wifi-connection

[George Shuklin]

During slow wifi-connection (f.e. lazy DHCP-server or low signal quality) unity-panel-service consume large part of cpu (up to 50%) while wifi-icon shows 'connecting' state.

That problem disappear after connection established, but during travel there is many slow or broken wifi-networks with very long connection interval. This cause high cpu load for long time (sometimes minutes and even hours if we get in situation of constant disconnecting) and, of cause, quick battery discharge.

Steps to reproduce:

Set up wifi network with dynamic IP without active DHCP-server
try to establish connection
Checks the cpu usage of unity-panel-service

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: unity-services 5.12-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic i686
.tmp.unity.support.test.0:

ApportVersion: 2.0.1-0ubuntu7
Architecture: i386
CompizPlugins: [core,bailer,composite,opengl,compiztoolbox,decor,imgpng,expo,scale,workarounds,move,place,gnomecompat,mousepoll,vpswitch,snap,wall,resize,grid,staticswitcher,unityshell]
CompositorRunning: compiz
Date: Thu May 17 18:33:55 2012
DistUpgraded: Fresh install
DistroCodename: quantal
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Device [17aa:21da]
Lsusb:
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
 Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
MachineType: LENOVO 4290RB3
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-24-generic root=UUID=ff771e68-857e-4d94-8f9a-90822e3deab4 ro crashkernel=384M-2G:64M,2G-:128M
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/01/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 8DET49WW (1.19 )
dmi.board.asset.tag: Not Available
dmi.board.name: 4290RB3
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr8DET49WW(1.19):bd07/01/2011:svnLENOVO:pn4290RB3:pvrThinkPadX220:rvnLENOVO:rn4290RB3:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 4290RB3
dmi.product.version: ThinkPad X220
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.7.8-0ubuntu1
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.2-0ubuntu4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.2-0ubuntu4
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu11
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20111219.aacbd629-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.17.0-1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Tomasz (0-tomasz-u)]

it happens with every panel change (eg: skype reconnecting)

[yuppie4ever (yuppie4ever)]

I use the indicator-multiload and unity-panel-service is always showing me about 5% CPU usage. This is very annoying. I believe this could be related.

[Gerry Boland (gerboland)]

Perhaps unrelated, but I find having skype running causes unity-panel-service to use mugh more CPU than normal. Watching it with top, it uses 100% of a cpu core on every alt-tab. Disabling skype, CPU usage looks more normal