Linux 4.18 Benefits from Energy-Aware Scheduling on ARM

The fourth major milestone release in 2018 for the Linux kernel was officially announced by Linus Torvalds on Aug. 12 with the general availability of Linux 4.18.

Linux 4.18 required a somewhat uncommon eight release candidates and follows the Linux 4.17 release that was announced on June 3.

“One week late(r) and here we are – 4.18 is out there,” Linus Torvalds wrote in his release announcement. “It was a very calm week, and arguably I could just have released on schedule last week, but we did have some minor updates.”

Features

Among the many capabilities added in the Linux 4.18 development cycle is one for energy-aware process scheduling, which is initially only supported on ARM.

“When cpufreq’s schedutil governor is selected, SCHED_DEADLINE implements the GRUB-PA [19] algorithm, reducing the CPU operating frequency to the minimum value that still allows to meet the deadlines,” the kernel pull message states.

Polling Improvements

Linux 4.18 also integrated a new asynchronous I/O interface that improves system polling performance.

“The changes were sponsored by Scylladb, and improve performance of the seastar framework up to 10 percent, while also removing the need for a privileged SCHED_FIFO epoll listener thread, kernel developers Christoph Hellwig wrote in a LKML thread.

ScyllaDB is a company that was co-founded by Avi Kivity, who is well known in the Linux kernel community for creating the Xen hypervisor. Scylla also created the seastar framework, which is a C++ framework used in the Scylla database.

Sean Michael Kerner is a senior editor at ServerWatch and InternetNews.com. Follow him on Twitter @TechJournalist.