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

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 Hardware Reviews
  1. NVIDIA GeForce GTX 970 Offers Great Linux Performance
  2. CompuLab Intense-PC2: An Excellent, Fanless, Mini PC Powered By Intel's i7 Haswell
  3. From The Atom 330 To Haswell ULT: Intel Linux Performance Benchmarks
  4. AMD Radeon R9 285 Tonga Performance On Linux
Latest Linux Articles
  1. Ubuntu 14.10 XMir System Compositor Benchmarks
  2. Btrfs RAID HDD Testing On Ubuntu Linux 14.10
  3. Ubuntu 14.10 Linux 32-bit vs. 64-bit Performance
  4. AMD Moves Forward With Unified Linux Driver Strategy, New Kernel Driver
Latest Linux News
  1. Open-Source, Linux Support For Corsair Link Devices Slowly Materializing
  2. Cairo-Dock 3.4 Shows A Lot Of Progress, Works Toward EGL/Wayland Support
  3. Mesa 10.4 Tentatively Planned For Early December
  4. SteamOS Update 145 Brings Compositor, Update Fixes
  5. GStreamer 2014 Conference Videos Posted: Wayland, HTML5, 3D
  6. Nouveau Now Supports DRI3 Without GLAMOR
  7. Features Of The Linux 3.18 Kernel
  8. Debian Now Defaults To Xfce On Non-x86 Desktops
  9. Phoenix Is Trying To Be An Open Version Of Apple's Swift
  10. Linux 3.19 To Have Skylake Graphics, PPGTT Enablement
Latest Forum Discussions
  1. HOPE: The Ease Of Python With The Speed Of C++
  2. Users/Developers Threatening Fork Of Debian GNU/Linux
  3. Ubuntu 16.04 Might Be The Distribution's Last 32-Bit Release
  4. AMD Releases UVD Video Decode Support For R600 GPUs
  5. Proof that strlcpy is un-needed
  6. xbox one tv tuner
  7. Bye bye BSD, Hello Linux: A Sys Admin's Story
  8. Updated and Optimized Ubuntu Free Graphics Drivers