Linux Sees Massive Performance Increase from a Single Line of Code
With one line of code, Intel was able to increase the performance of the Linux kernel by 4,000 percent.
You read that right; a single line of code from Intel has shown the Linux kernel could receive a performance jump of up to 4,000 percent by way of will-it-scale.per_process_ops.
A Intel kernel testing bot discovered this, and the change was added to commit efa7df3e3bb5 (“mm: align larger anonymous mappings on THP boundaries”). That commit was related to efficient memory management and mapping (mm and mmap) techniques that use Transparent Hugepages (THPs) and Page Middle Directory (PMD).
Before anyone gets too excited, the discovered performance increase was isolated to a synthetic test case, so real-world workloads will probably never see such incredible gains. However, it does make a solid case for how well Linux is capable of performing.
One issue with the change is that it was shown to significantly regress certain workloads by up to 600 percent (when using the cactusBSSN benchmark on certain platforms). Those regressions are related to the benchmark's access pattern that suffers from translation lookaside buffer (TLB) or cache aliasing from aligned boundaries of the individual areas.
According to author Vlastimil Babka from SUSE, “To fix the regression but still try to benefit from THP-friendly anonymous mapping alignment, add a condition that the size of the mapping must be a multiple of PMD size instead of at least PMD size. In case of many odd-sized mapping like the cactusBSSN creates, those will stop being aligned and with gaps between, and instead naturally merge again.”
You can read more about this discovery from this entry in the Kernel mailing list and this post from Vlastimil Babka.
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.
News
-
Framework Laptop 13 Pro Competes with the Best
Framework has released what might be considered the MacBook of Linux devices.
-
The Latest CachyOS Features Supercharged Kernel
The latest release of CachyOS brings with it an enhanced version of the latest Linux kernel.
-
Kernel 7.0 Is a Bit More Rusty
Linux kernel 7.0 has been released for general availability, with Rust finally getting its due.
-
France Says "Au Revoir" to Microsoft
In a move that should surprise no one, France announced plans to reduce its reliance on US technology, and Microsoft Windows is the first to get the boot.
-
CIQ Releases Compatibility Catalog for Rocky Linux
The company behind Rocky Linux is making an open catalog available to developers, hobbyists, and other contributors, so they can verify and publish compatibility with the CIQ lineup.
-
KDE Gets Some Resuscitation
KDE is bringing back two themes that vanished a few years ago, putting a bit more air under its wings.
-
Ubuntu 26.04 Beta Arrives with Some Surprises
Ubuntu 26.04 is almost here, but the beta version has been released, and it might surprise some people.
-
Ubuntu MATE Dev Leaving After 12 years
Martin Wimpress, the maintainer of Ubuntu MATE, is now searching for his successor. Are you the next in line?
-
Kali Linux Waxes Nostalgic with BackTrack Mode
For those who've used Kali Linux since its inception, the changes with the new release are sure to put a smile on your face.
-
Gnome 50 Smooths Out NVIDIA GPU Issues
Gamers rejoice, your favorite pastime just got better with Gnome 50 and NVIDIA GPUs.