Linux 4.15 Will Have A Scheduler Change To Benefit AMD EPYC

Linux 4.15 will be exciting for AMD Zen systems not only for working temperature reporting (finally) being in place for Ryzen/EPYC, but AMD EPYC CPUs should also benefit from a scheduler topology improvement.

Suravee Suthikulpanit of AMD has been working on a patch for Family 17h / EPYC systems where currently the kernel's setup of scheduler domains is less than optimal with not being properly balanced across the NUMA nodes.

The current kernel's behavior can lead to cases where tasks aren't properly balanced across logical NUMA nodes. In other cases, threads are scheduled for the same CPU while other CPU cores could be idling, yielding an inconsistency in performance.

With the patch now being tested via linux-next, it introduces the concept of a NUMA identity node sched domain to address the potential for improper load balancing. All the details within this patch that's pending for Linux 4.15.

If you haven't already, be sure to check out our many AMD EPYC Linux benchmarks. More are on the way.