Linux 5.0 Arrives With FreeSync Support, Spectre Mitigations

By Nathaniel Mott March 5, 2019 at 7:52 AM

Credit: Imagentle/ShutterstockCredit: Imagentle/Shutterstock

Linux 5.0 released this week, with its headlining features being the addition of FreeSync support and Spectre vulnerability fixes.

The kernel's FreeSync support comes with a few asterisks. Games running on the Vulkan API aren't yet supported. Mesa won't let desktop compositors, web browsers or media players enable the feature, and it has to be configured without a graphical user interface (GUI).

Still, this is a start, and Linux 5.0 users interested in enabling FreeSync should check out Phoronix's guide to doing so. The setup requires all the appropriate hardware--a FreeSync compatible monitor and graphics card--as well as an assortment of drivers.

Linux 5.0 also includes Spectre mitigations that are supposed to defend against the popular side-channel attack without incurring serious performance hits. A previous kernel release (4.20) incurred up to a 50 percent performance penalty on some Intel processors.

Phoronix tested the new kernel's performance and found the penalty varies by CPU. It saw a 13 percent hit on an Intel Core i9-7980XE, a 14 percent hit on an AMD Ryzen 7 2700X and a 17 percent hit on an Intel Core i7-8086K, based on the geometric mean of all tests.

Those numbers are unlikely to make people happy. Anyone who buys a CPU won't be pleased to find out securing it results in a double-digit performance drop. Still, a 17 percent performance decline is better than a 50 percent one.

There are many other features in the Linux 5.0 release. But Linus Torvalds, principal developer of the Linux kernel, noted that this isn't why it's a full point release.

"The overall changes for all of the 5.0 release are much bigger," he said in a message about the release. "But I'd like to point out (yet again) that we don't do feature-based releases and that '5.0' doesn't mean anything more than that the 4.x numbers started getting big enough that I ran out of fingers and toes."