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 Benchmarking Platform
Phoromatic Test Orchestration

Uff Da! The Linux Power Bug Even More Mysterious

Intel

Published on 22 April 2011 04:23 PM EDT
Written by Michael Larabel in Intel
6 Comments

In continuation of Mobile Users Beware: Linux Has Major Power Regression, what's causing this regression in the mainline Linux kernel between Linux 2.6.37 and 2.6.38 (and still outstanding in 2.6.39) is still a mystery. To some surprise, even when disabling power management on one of the ThinkPads, the problem is still present.

In the article published earlier, it was shown that this major performance regression that's affected multiple notebooks of several CPU generations and GPUs of different vendors isn't attributed to any back-light differences, EIST (Enhanced Intel SpeedStep Technology) was still functioning for dynamically changing the CPU clock/voltage states, and there are no other obvious differences.

The latest test to be carried out was to see what would happen when disabling "Intel SpeedStep" and "CPU Power Management" from the BIOS of the Lenovo ThinkPad T60 with the Core Duo T2400. When doing so and testing both the 2.6.37 and Linux 2.6.38 kernels, the problem still persisted.

This power issue is even to the extent that a Linux 2.6.37 kernel when EIST/CPU-PM (Power Management) is disabled from the BIOS that under that condition it even consumes less power than a Linux 2.6.38 kernel when the power management and SpeedStep Technology are enabled.

So disabling EIST / CPU power management from the BIOS of the ThinkPad seems to have no impact on this dramatic regression.

The only common denominator so far is that it's occurring on Intel hardware. However, that's all I've been able to test on as far as mobile devices are concerned. All of the netbooks / notebooks here are Intel powered and for desktops / workstations / servers it's also skewed towards Intel by a factor of 6~9 to 1 AMD. That's simply because AMD hasn't been sending out any processors or other hardware to Phoronix (the last time was Opterons a few generations ago), so the AMD hardware around is usually limited to what I end up purchasing. Intel hardware is much easier to come by. When buying any notebooks, they tend to be ThinkPads or Mac Book Pros, which also trend towards Intel. Unfortunately for the AMD desktops and servers, there isn't the power monitoring support as mentioned in the earlier article.

There's also now at least one Phoronix reader who has also noticed issues with Linux 2.6.38+ and as a result is still using the Linux 2.6.37 kernel.

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 News
  1. KDE Applications 15.04.3 Fixes Bugs
  2. Benchmarks Of 54 Different Intel/AMD Linux Systems
  3. Linux 4.2 Bringing Support For ARCv2, HS38 CPU Cores
  4. Libdrm 2.4.62 Is An Important Update For Open-Source GPU Drivers
  5. The State of Unity 3D Game Engine, Editor On Linux
  6. ZFS On Linux 0.6.4.2 Brings Linux 4.1 Support, Fixes
  7. Old Net Burst Tests, Ubuntu Phone & Assembly x86 Were Popular Topics Last Month
  8. Qt 5.5 Officially Released
  9. Global Shortcuts In KDE Plasma Under Wayland
  10. LLVMpipe FP64 Support Knocks Off Some GL4 Extensions
Latest Articles & Reviews
  1. How KDE VDG Is Trying To Make Open-Source Software Beautiful
  2. Attempting To Try Out BCache On The Linux 4.1 Kernel
  3. CompuLab's Fitlet Is A Very Tiny, Fanless, Linux PC With AMD A10 Micro
  4. AMD A10-7870K Godavari: RadeonSI Gallium3D vs. Catalyst Linux Drivers
Most Viewed News This Week
  1. Kubuntu 15.10 Could Be The End Of The Road
  2. NVIDIA Starts Supplying Open-Source Hardware Reference Headers
  3. KDBUS Won't Be Pushed Until The Linux 4.3 Kernel
  4. The State & Complications Of Porting The Unity Editor To Linux
  5. The Staging Pull For Linux 4.2: "Big, Really Big"
  6. Latest Rumor Pegs Microsoft Wanting To Buy AMD
  7. SteamOS "Brewmaster" Is Valve's New Debian 8.1 Based Version
  8. Jonathan Riddell Steps Down From The Kubuntu Council