This bug has been open on the Ubuntu bugzilla (Launchpad) for two years
The only way to get it fixed is for someone to attract the kernel developers attention.....
These test results should be added to with some powertop runs and results reported. I am beyond frustration over this matter. It reflects very badly on linux.
This issue has been in the Ubuntu Launchpad system for two years now:
It needs reporting to the kernel bugzilla. The results here plus powertop output would be good. Someone familiar with kernel development needs to do this (not me unfortunately).
[Offtopic] Idea for PTS: ability to zoom in graphs.
I recently discovered a bug in my wifi adapter that causes terrible performance with power management activated. This started around the time the kernel I'm running got updated to 2.6.38, so it seems the power management area really needs a bit more attention.
Maybe I'm just stating the obvious but have you compared the kernel .config files with each other? For instance, if the default config starts using a higher CONFIG_HZ setting you'll have a much different amount of ticker timer irqs, and, potentially, task reschedulings happening. Same with CONFIG_HZ vs tickerless modes etc. Just a thought.