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

LTO Support Coming To Linux 3.15, Making For A Faster Kernel

Linux Kernel

Published on 07 April 2014 04:49 PM EDT
Written by Michael Larabel in Linux Kernel
13 Comments

As a potentially significant performance win for the Linux kernel, when compiling the Linux kernel support for link-time optimizations (LTO) are now supported.

Earlier in April I wrote about link-time optimization support for the kernel nearing reality. LTO support for the Linux kernel has been in the works since 2012 but only with Linux 3.15 will it become a mainline possibility. Link-Time Optimizations via GCC and other compilers allow for various compile-time optimizations to be applied across the binary as a whole. Enabling link-time optimizations can yield some significant performance improvements but results in much slower compile times and with large programs can cause problems due to the size of optimizing the complete binary at once.

As explained in the earlier article, the work back in 2012 by Intel developers showed the kernel compile time increased by two to four times and needed 4~9GB of memory to complete the task. However, it was found the resulting Linux kernel image was faster in various benchmarks.

Sent in today by Michal Marek was LTO Kbuild support for Linux 3.15. "It is a separate branch, because it depends on other patches by Andi which were merged through other trees. The link-time-optimization build is an experimental feature, so there one kconfig option to enable it and another kconfig option to disable it (behind a door with a sign 'Beware of the Leopard'...), so that it is not enabled by allmodconfig/allyesconfig."

So it's still a very experimental feature, but it will land for the Linux 3.15 kernel. There's been no recent benchmark results shared of Linux 3.15 with LTO support, but as soon as the release candidates start coming out, we'll proceed to benchmark it at Phoronix. Generating a link-time optimized kernel also requires a new version of binutils and with the GCC 4.9 compiler are many LTO improvements. Stay tuned for benchmarks!

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. Intel Pentium G3258 On Linux
  2. SilverStone Precision PS10
  3. ASRock Z97 Extreme6
  4. Nouveau Re-Clocking Is Way Faster, Shows Much Progress For Open-Source NVIDIA
Latest Linux Articles
  1. X.Org Server 1.16 Officially Released With Terrific Features
  2. Ubuntu With Linux 3.16 Smashes OS X 10.9.4 On The MacBook Air
  3. Preview: Benchmarking CentOS 7.0 & Scientific Linux 7.0
  4. Linux 3.16 File-System Tests On A Hard Drive
Latest Linux News
  1. The Linux Kernel Bang-Bang Thermal Governor Is Banging
  2. NVIDIA Releases K1-Powered Shield Tablet & Controller
  3. Xen Project Announces Mirage OS 2.0
  4. Canonical Community Team Changes Announced For Ubuntu
  5. Raspberry Pi B+ ARM Debian Benchmarks
  6. Mozilla Unleashes Firefox 31 Web Browser
  7. GCC 5.0 Is Expected Next Year
  8. PHP5's Successor Might Be PHP7
  9. AMD "Hawaii" Open-Source GPU Acceleration Still Not Working Right
  10. AMDKFD Driver Still Evolving For Open-Source HSA On Linux
Latest Forum Discussions
  1. AMD "Hawaii" Open-Source GPU Acceleration Still Not Working Right
  2. Next-Gen OpenGL To Be Announced Next Month
  3. Ubuntu With Linux 3.16 Smashes OS X 10.9.4 On The MacBook Air
  4. Updated and Optimized Ubuntu Free Graphics Drivers
  5. AMD Publishes Open-Source Linux HSA Kernel Driver
  6. KDE Plasma 5 Officially Released
  7. Vote For GOG To Make Galaxy Open Source
  8. TSC Problem on Gigabyte GA-X79-UP4 (rev 1.1)