Linux 5.3 Kernel Yielding The Best Performance Yet For AMD EPYC "Rome" CPU Performance

Among many different Linux/open-source benchmarks being worked on for the AMD EPYC "Rome" processors now that our initial launch benchmarks are out of the way are Linux distribution comparisons, checking out the BSD compatibility, and more. Some tests I wrapped up this weekend were seeing how recent Linux kernel releases perform on the AMD EPYC 7742 64-core / 128-thread processors.

For some weekend analysis, here are benchmarks of Linux 4.18 through Linux 5.3 in its current development form. All tests were done on the same AMD EPYC 7742 2P server running Ubuntu 19.04 and using the latest kernels in each series via the Ubuntu Mainline Kernel PPA.

Via the Phoronix Test Suite, various benchmarks were run for looking at the performance between the tested kernels.

In most of the CPU bound workloads, there are only slightly variations in the performance, but at least Linux 5.3 is generally edging slightly higher than recent kernels.

Linux 4.18 largely seems to be the recommended minimum kernel version for these new AMD EPYC processors. On older kernels the system will boot and work, but there are various dmesg bits about CPPC not being supported and also x2apic support was added in 4.18. But as I generally recommend with any new hardware: the newer, the better both for features and the best performance.




The various synthetic kernel tests are generally showing the kernel moving in the right direction for performance.




In real-world workloads, there is generally slight performance advantages in many instances to being on Linux 5.2 or newer.

When cutting to the geometric mean for looking at the direction of the kernel performance across dozens of different benchmarks, Linux 5.3 delivered the best performance of the kernels tested on Ubuntu with this dual AMD EPYC 7742 server. I'll be running more benchmarks shortly as well as seeing if some of these Linux 5.3 wins are limited to the latest AMD processors or more widespread optimizations; see our Linux 5.3 feature overview to learn about the changes in this upcoming kernel release. Linux 5.3 should make it out as stable in September and be found by the likes of Ubuntu 19.10 and Fedora 31 while the Linux 5.4 cycle will kick off a new dance.