1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

The Linux Kernel Is Still On A Power Binge

Linux Kernel

Published on 18 May 2011 08:32 AM EDT
Written by Michael Larabel in Linux Kernel
14 Comments

It's been about three weeks since last mentioning the major power consumption problem in the Linux kernel (actually, there's more than one power regression) and it's affecting distributions like Ubuntu 11.04. The lack of mentioning the power regression in recent weeks isn't though because the regressions are addressed, they are still outstanding with the about to be released Linux 2.6.39 kernel.

The power regressions just haven't been mentioned recently since I've been out of the office since late last month due to UDS Budapest, LinuxTag 2011, and beer drinking with Phoronix readers in Bavaria and around Germany. Now that I'm back to the usual workload, I've run some more kernel tests to verify the increased power consumption is still there with the latest upstream kernel. Sadly, the issue is still there.

There's many more realizing as well that they are affected by this bug based upon the Ubuntu bug report and user experiences within the Phoronix Forums, Ubuntu Forums, etc.

With the Linux 2.6.39 kernel using the Linus Torvalds tree as of last night (17 May), the issue is still very much present when tested on one of the Lenovo ThinkPad notebooks with an Intel Core 2 Duo CPU.

Earlier this month while I was away there was some speculation that the cause of at least one of these power regressions was due to some SMP / tick-less changes in the recent kernels. In particular, this LKML thread from last September was referenced by a user commenting on the Ubuntu bug report. The thought was for SMP (multi-core) systems the load balancing tick was keeping the system up excessively.

Beyond testing the very latest kernel Git to verify its existence, I also ran a test this morning of the kernel in its default SMP kernel configuration and then again when it was booted with the nosmp flag at boot-time (and separately, with maxcpus=1 as well just to ensure no differences) so that the dual-core Intel CPU was only being treated as single-threaded.

The Linux Kernel Is Still On A Power Binge


This didn't help things and the kernel is still on a power binge. Testing continues.

Additionally, if anyone has any recommendations about UPS power systems that have a USB interface and support monitoring the power consumption under Linux via a sysfs node or similar, knowing that would be much appreciated. (Or any UPS vendors willing to send one out to Phoronix would be really great!) This would greatly expedite the testing process due to much faster desktop/server/workstation hardware around here and would allow to see the full scope of hardware affected by this major Linux power problem rather than relying upon notebook battery consumption monitoring.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Linux Hardware Reviews
  1. Preview: AMD's FX-9590 Eight-Core At Up To 5.0GHz On Linux
  2. Intel Launches The Core i7 5960X, Mighty Powerful Haswell-E CPUs
  3. AMD Radeon R9 290: Gallium3D vs. Catalyst Drivers
  4. AMD Radeon R9 290 Open-Source Driver Works, But Has A Ways To Go
Latest Linux Articles
  1. Ondemand vs. Performance CPU Governing For AMD FX CPUs On Linux 3.17
  2. How Intel Graphics On Linux Compare To Open-Source AMD/NVIDIA Drivers
  3. The Fastest NVIDIA GPUs For Open-Source Nouveau With Steam Linux Gaming
  4. Testing For The Latest Linux Kernel Power Regression
Latest Linux News
  1. Marek Lands Radeon Gallium3D HyperZ Improvements
  2. Mozilla Firefox 32 Surfaces With HTML5, Developer Changes
  3. Nouveau X.Org Driver Released With DRI3+Present, Maxwell, GLAMOR
  4. Microsoft & AMD Release C++ AMP Compiler With Linux Support
  5. AMD, Wine & Valve Dominated August For Linux Users
  6. Linux 3.17-rc3 Kernel Released Back On Schedule
  7. Lennart Poettering Talks Up His New Linux Vision That Involves Btrfs
  8. Mesa 10.3 RC2 Arrives Via Its New Release Manager
  9. Ubuntu 14.10's Lack Of X.Org Server 1.16 Gets Blamed On AMD
  10. MSI Motherboard BIOS Updating Remains A Pain For Linux Users
Latest Forum Discussions
  1. AMD graphics doesn't work with AMD Catalyst drivers
  2. Lennart Poettering Talks Up His New Linux Vision That Involves Btrfs
  3. Best Radeon for a Power Mac G5?
  4. The dangers of Linux kernel development
  5. Updated and Optimized Ubuntu Free Graphics Drivers
  6. AMD Releases UVD Video Decode Support For R600 GPUs
  7. SSD seems slow
  8. Is laptop with Intel CPU and AMD dGPU worth buying considering especially AMD Enduro?