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

Ubuntu 32-bit, 32-bit PAE, 64-bit Kernel Benchmarks

Michael Larabel

Published on 30 December 2009
Written by Michael Larabel
Page 1 of 5 - 41 Comments

Coming up in our forums was a testing request to compare the performance of Linux between using 32-bit, 32-bit PAE, and 64-bit kernels. This is coming after Linus Torvalds has spoke of 25% performance differences between kernels using CONFIG_HIGHMEM4G and those without this option that allows 32-bit builds to address up to 4GB of physical RAM on a system. We decided to compare the performance of the 32-bit, 32-bit PAE, and 64-bit kernels on a modern desktop system and here are the results.

For this comparison we used Ubuntu 9.10 on a Lenovo ThinkPad T61 notebook running an Intel Core 2 Duo T9300 processor, 4GB of system memory, a 100GB Hitachi HTS7220 SATA HDD, and a NVIDIA Quadro NVS 140M. We were using the Ubuntu-supplied kernels that are based off the Linux 2.6.31 kernel in Ubuntu Karmic. Other packages that were maintained included GNOME 2.28.1, X Server 1.6.4, NVIDIA 195.22 display driver, GCC 4.4.1, and we were using the default EXT4 file-system with all other defaults. With Ubuntu to properly address 4GB or greater of system memory you need to use a PAE kernel as the Physical Address Extension support through the kernel's high-mem configuration options are not enabled in the default 32-bit kernels. CONFIG_HIGHMEM4G is enabled in the default Ubuntu kernel, but the Ubuntu PAE kernel uses CONFIG_HIGHMEM64G (and other build options) for handling up to 64GB of system memory. Of course, with 64-bit addressing there is not this greater than 4GB RAM limitation. Though even with a 32-bit non-PAE kernel the system will only report 3GB of system memory by default due to 1GB of that being reserved for kernel virtual addresses while the 3GB is available to user-space addresses.

The only differences in the kernel configuration between Ubuntu's PAE and non-PAE 32-bit kernels are enabling the CONFIG_X86_CMPXCHG64, CONFIG_HIGHMEM64G instead of CONFIG_HIGHMEM4G, CONFIG_X86_PAE, CONFIG_ARCH_PHYS_ADDR_T_64BIT, CONFIG_PHYS_ADDR_T_64BIT, CONFIG_I2O_EXT_ADAPTEC_DMA64, and disabling CONFIG_ASYNC_TX_DMA. The rest of the kernel configuration is the same. The Linux kernel also requires that the CPU itself supports PAE, but these days that is practically all Intel and AMD processors.

Among the tests we ran on the three Linux 2.6.31 kernels with the Phoronix Test Suite were OpenArena, Apache, PostgreSQL, Bullet, C-Ray, Gcrypt, GnuPG, GraphicsMagick, timed MAFFT alignment, John The Ripper, OpenSSL, x264, and PostMark.

With the ioquake3-powered OpenArena game there were virtually no performance differences between the 32-bit, 32-bit PAE, and 64-bit kernels. We had ran other OpenGL-powered tests too through the Phoronix Test Suite and found no significant differences, so we are just sharing one set of numbers in this article to avoid repetition.

While the different kernels had not affected the gaming performance with our Core 2 Duo laptop running with 4GB of system memory, the Apache performance was significantly affected. The stock Ubuntu 32-bit kernel had managed to 473 requests per second while the PAE kernel dropped just slightly with its 467 request average, but meanwhile the 64-bit support was many times faster with its 7,989 requests per second count.

<< Previous Page
1
Latest Linux Hardware Reviews
  1. MSI X99S SLI PLUS On Linux
  2. NVIDIA GeForce GTX 970 Offers Great Linux Performance
  3. CompuLab Intense-PC2: An Excellent, Fanless, Mini PC Powered By Intel's i7 Haswell
  4. From The Atom 330 To Haswell ULT: Intel Linux Performance Benchmarks
Latest Linux Articles
  1. RunAbove: A POWER8 Compute Cloud With Offerings Up To 176 Threads
  2. 6-Way Ubuntu 14.10 Linux Desktop Benchmarks
  3. Ubuntu 14.10 XMir System Compositor Benchmarks
  4. Btrfs RAID HDD Testing On Ubuntu Linux 14.10
Latest Linux News
  1. Fedora 21 Beta & Final Release Slip Further
  2. Mesa 10.3.2 Has A Couple Bug-Fixes
  3. RadeonSI/R600g HyperZ Support Gets Turned Back On
  4. openSUSE Factory & Tumbleweed Are Merging
  5. More Fedora Delays: Fedora 21 Beta Slips
  6. Mono Brings C# To The Unreal Engine 4
  7. Coreboot Now Has Support For Intel Broadwell Hardware
  8. Enlightenment's EFL 1.12 Alpha Has Evas GL-DRM Engine, OpenGL ES 1.1 Support
  9. GTK+ Lands Experimental Backend For Mir Display Server
  10. Ubuntu 14.10 Officially Released
Latest Forum Discussions
  1. AMD Radeon VDPAU Video Performance With Gallium3D
  2. HOPE: The Ease Of Python With The Speed Of C++
  3. Updated and Optimized Ubuntu Free Graphics Drivers
  4. Ubuntu 16.04 Might Be The Distribution's Last 32-Bit Release
  5. Linux hacker compares Solaris kernel code:
  6. Advertisements On Phoronix
  7. Users/Developers Threatening Fork Of Debian GNU/Linux
  8. AMD Releases UVD Video Decode Support For R600 GPUs