[Sandy Bridge] serious power regression from kernel 3.0.0-6 to 3.0.0-7 (rc6 disabled)
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Linux |
Fix Released
|
Medium
|
|||
The Ubuntu Power Consumption Project |
Fix Released
|
Undecided
|
Unassigned | ||
linux (Ubuntu) |
Fix Released
|
Medium
|
Canonical Kernel Team | ||
Oneiric |
Won't Fix
|
Medium
|
Unassigned | ||
Precise |
Fix Released
|
Medium
|
Canonical Kernel Team |
Bug Description
On Ubuntu Oneiric, I discovered a serious power regression from Kernel 3.0.0-6-generic to 3.0.0-7-generic.
It is on an Intel Sandy Bridge Laptop. Unplugging the laptop from ac power source I made the tests without any graphical user interface active with the same brightness and other settings. When I boot into the kernels I have the following idle power numbers with
grep rate /proc/acpi/
- Kernel 3.0.0-6: present rate: 1530-1560mW
- Kernel 3.0.0-7: present rate: 1950-2020mW
It is a more than 30% (!!!) increase in power usage withe the same hw, same settings, different Kernel version.
Which is really annoying as the laptop fans start working above 1700-1800mw, so it is night and day in usage comfort the laptop with the two kernels.
Here is the kernel log for both versions:
Log with 3.0.0-6: http://
Log with 3.0.0-7: http://
Please let me know if you need any more data on this.
The problem is 100% reproducible.
Changed in linux (Ubuntu): | |
importance: | Undecided → Medium |
status: | New → Triaged |
summary: |
- Serious power regression from kernel 3.0.0-6 to 3.0.0-7 (30% more power - at idle) + Sandy Bridge serious power regression from kernel 3.0.0-6 to 3.0.0-7 + (30% more power at idle) |
Changed in linux (Ubuntu Oneiric): | |
status: | New → Triaged |
importance: | Undecided → Medium |
tags: | added: kernel-key |
Changed in linux: | |
importance: | Unknown → Medium |
status: | Unknown → Fix Released |
Changed in linux (Ubuntu Precise): | |
assignee: | nobody → Canonical Kernel Team (canonical-kernel-team) |
Changed in ubuntu-power-consumption: | |
status: | New → Confirmed |
Changed in ubuntu-power-consumption: | |
status: | Confirmed → Fix Released |
tags: | removed: kernel-key |
Changed in linux (Ubuntu Oneiric): | |
status: | Triaged → Won't Fix |
It's a Sandy Bridge machine, so commit kernel. ubuntu. com/git? p=ubuntu/ ubuntu- oneiric. git;a=commit; h=05bd42688dbc0 66d4e2689b6f73c 0470601f788b
http://
(added in 3.0.0-7.8) might be causing the regression. Try re-enabling rc6 and see if that makes a difference?