Is "laptop-mode-tools" still relevant for 12.04 and the 3.x kernels?
I'm using Ubuntu 12.04 x64 and trying to choose power management software. Laptop-mode-tools have a lot of features, but the only reason why I'm worry about is that it's manual and config files are written like for Linux 2.6 kernel. But Ubuntu currently has 3.2 kernel version, and, as I know, it has a lot of powersaving improvements. That's why:
- laptop-mode-tools may be obsolete;
- laptop-mode-tools may conflict with new kernel features and destabilize the system.
So, the question is - are laptop-mode-tools still relevant for Ubuntu 12.04 or Ubuntu handles this stuff good by itself?
Solution 1:
The changes we put into Precise 12.04 LTS pm-utils /usr/lib/pm-utils/power.d address a lot of the best low-risk power savings for a broad range of machines based on some in-depth analysis with a high precision multimeter. These scripts cover power savings using hdparm, Intel Audio powersavings, PCI device power savings, PCI-e ASPM, USB bluetooth, SATA ALPM, Wireless, scheduler tweaks and VM dirty page settings.
I suspect these changes in 12.04 are a little more comprehensive than the laptop-mode-utils.
For a write up of the testing used for the 12.04 pm-util chanages please refer to:
- http://kernel.ubuntu.com/~cking/power-benchmarking/pm-utils-results/results.txt
- http://kernel.ubuntu.com/~cking/power-benchmarking/pm-utils-results/pm-tests.ods
We also did a lot of analysis of the PowerTop power saving recommendations that proved to work well (and reliably) across a range of machines and incorporated these into the pm-utils power.d scripts (see http://kernel.ubuntu.com/~cking/power-benchmarking/powertop-good-bad-recommendations) and we ran some community based crowd-sourcing to test these changes, see:
- https://wiki.ubuntu.com/Kernel/PowerManagementPMUtils
I hope that throws some light into the kinds of savings one can achieve with the updated pm-utils scripts.
For more details about ways to save power, please also consult:
- https://wiki.ubuntu.com/Kernel/PowerManagement