Just in time for Christmas, Linus Torvalds officially announced the general availability of the Linux 4.20 kernel on Dec. 23.
The Linux 4.20 kernel is the sixth and final major new Linux kernel release of 2018, which was a year of innovation and challenge for Linux. The Linux 4.20 kernel adds new hardware support and performance improvements, that boost the open source server operating system's capabilities.
"Have a Merry Christmas or other holiday of your choice," Torvalds wrote in in his Linux 4.20 release announcement.
Linux 4.20 Features
Among the many new capabilities added in Linux 4.20 is new hardware support for multiple processor architectures. For x86, support has been added for the Hygon Dhyana Family 18h. Support of the new Qualcomm Snapdragon 825 SoC that is used in both mobile phones and laptops, has also been added.
There is also a new feature that will enable the DNS resolver in Linux to retrieve a server set of multiple addresses.
"Allow the DNS resolver to retrieve a set of servers and their associated addresses, ports, preference and weight ratings," Linux kernel develop David Howells wrote in his Linux code commit message.
Also of note is the implementation of support for Intel's 2.5 Gbps Ethernet controller. Standard Cat5 Ethernet cables are now able to support faster speeds of 2.5 and 5 Gbps, though in order to take advantage of that capability, hardware controllers like those from Intel are needed.
Linux 4.20 also introduces code that could make encrypted network connections run faster, thanks to support for async encryption of records for performance in TLS. In his commit message, Linux kernel developer Vakul Garg explained that the way TLS encryption generally works in Linux today is that records are encrypted & transmitted serially. Garg commented that the current approach only encrypts one record at a time which is inefficient when asynchronous crypto accelerators are used.
"This patch enables encryption of multiple records in parallel when an async capable crypto accelerator is present in system," Garg wrote.
Linux 4.20 also introduces over 20 different improvements to help boost performance for the Btrfs filesystem.
"Preliminary results show eg. more files/sec in fsmark, better perf on multi-threaded workloads (filebench, dbench), fewer context switches and overall better memory allocation characteristics (multiple benchmarks)," Linux kernel developers David Sterba wrote in his Git Pull request.
Linux in 2018
The Linux 4.20 kernel follows the Linux 4.19 update which became generally available on Oct. 22. Among the big improvements that landed in Linux 4.19 was improved latency.
Linux 4.18 was released on Aug. 12 providing energy-aware scheduling capabilities for ARM processors.
Linux 4.17 came out on June 3, bringing with it, the Linux Kernel Memory Consistency Module (LKMM).
Linux 4.16 was not a joke, though it was release on April 1. Linux 4.16 introduced usercopy whitelisting capabilities which can help to reduce the potential memory attack surface in Linux.
Linux 4.15 was the first Linux kernel of 2018 and was released on Jan. 28 after nine release candidates, making it the longest Linux kernel development cycle since 2011. Linux 4.15 was interesting for several other reasons, the most notable being that it was the first to provide formal patches for the Meltdown and Spectre vulnerabilities that became public at the beginning of the year.
Sean Michael Kerner is a senior editor at ServerWatch and InternetNews.com. Follow him on Twitter @TechJournalist.