unity-panel-service is using a constant 1% of one of my cores on an Intel i7-2600 according to top, while the desktop is totally idle. When I switch to another VT, it makes no difference and unity-panel-service just keeps using the CPU.
This obviously should not happen and will impact on battery life of notebooks. Also, using the CPU constantly negates the power-saving benefits of a tickless Linux kernel (http://www.lesswatts.org/projects/tickless/).
Update: Found the cause to be that my indicator-datetime is set to display seconds, not just hours and minutes. This seems to cause unity/compiz to send the SyncOne and SyncGeometries dbus messages to unity-panel-service every second. And profiling unity-panel-service with callgrind shows it is spending all it's time in g_variant_ fuctions, invoked by the dbus activity. So this needs to be optimized. It's quite wrong that something happening only once per second should use so much CPU.
ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: unity 3.8.16-0ubuntu1~natty1
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic 2.6.38.7
Uname: Linux 2.6.38-10-generic x86_64
NonfreeKernelModules: fglrx
Architecture: amd64
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,vpswitch,place,imgpng,regex,unitymtgrabhandles,grid,session,snap,mousepoll,resize,move,animation,expo,ezoom,workarounds,resizeinfo,wall,staticswitcher,fade,scale,unityshell]
Date: Wed Jul 20 17:34:24 2011
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1)
ProcEnviron:
LANGUAGE=en_AU:en
LANG=en_AU.UTF-8
SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
See also related, but different bug 785648.