Kernel Bug Means Linux Power Usage Remains High

An anonymous reader writes "The significant Linux kernel power regression reported back in April, which ended up being attributed to PCI-E Active State Power Management, is still not resolved even as Ubuntu 11.10 and Fedora 16 approach. Until Linux is able to handle ASPM in a manner more like Windows or the device drivers explicitly set the ASPM flag, users of many modern laptops need to use the "pcie_aspm=force" option to regain much of their battery life. At least a power bug affecting newer Intel hardware with the "energy performance bias" feature has been fixed. There's more information in this LaunchPad bug report and in the latest power consumption testing."

Comments

It is not something that can be resolved...

[kvvbassboy]

It's a problem with the BIOS manufacturers, and the BIOS incorrectly reporting its ASPM capability. When an OEM installs Windows on a laptop, it can correctly tune these settings. But for a fresh install of Linux that YOU performed, a database of every motherboard + BIOS combination needs to be maintained in the open to set the force PCIE ASPM flag. If set wrongly, when the BIOS doesn't support it, it could lead to locking which is far more serious.

There are other solutions to effectively manage power in Linux, like Jupiter.

For more (and better) information, see the following links: About the Kernel 3.0 "Power Regression" Myth and PCIe, power management, and problematic BIOSes

Re:Intel?

[Anonymous Coward]

It's a motherboard issue. BIOS supports ASPM but doesn't advertise it => Linux doesn't try using hardware that isn't there => power usage goes up => Linux gets blamed. Fucking Microsoft.

Why bother?

[msobkow]

The marginal performance improvements you get by tweaking kernel settings will not make one whit of difference to the average user unless there is a glaring performance issue like the power drain currently being discussed.

Grandma isn't going to install Linux on her laptop -- you are. And as the technically knowledgeable person, you should be doing any such tweaking. Other systems have the benefit of the OEM doing the tweaking and tuning, but it does get done by somebody. Don't blame Linux for not doing something automagically that other systems don't do, either.

"...most linux development is primarily focused on servers..."

I don't believe that's true. While server tweaks get the press, there is a lot of effort put into the desktop experience as well. You're just far more likely to hear about kernel tweaks that are useful for desktop performance from the "real time systems" people.