FSGSBASE Patches Sent Out An 11th Time For Boosting CPU Performance Back To Ivy Bridge

The FSGSBASE patches for the Linux kernel have been sent out for their 11th time over the past few years to make use of this CPU instruction supported going back to Ivy Bridge hardware.

Microsoft's Sasha Levin has been the latest developer taking a stab at trying to get the FSGSBASE support merged. See last month's article for the current state.

We benchmarked an earlier version of these patches to find some performance benefits indeed. There are performance benefits including for context switching and other areas that have been harmed in recent years by all of the CPU vulnerability mitigations.

FSGSBASE support is found on Intel CPUs going back to Ivy Bridge. On the AMD side it's there with Zen processors. FSGSBASE support can be checked by looking for its flag in /proc/cpuinfo.

On Saturday was the 11th spin of these patches from Sasha. We'll see where this goes and if we could potentially see FSGSBASE wired up for Linux 5.8 or if the waiting game will continue.