The second weekly release candidate of Linux 5.6 is now available and overall it's quite a calm test release.

A new driver already queued in the power management code for the Linux 5.7 cycle not opening up until April is a "tiny power button" driver.

Since the release of Linux 5.6-rc1 that is coming in as a very feature-packed kernel, here are benchmarks of Linux 5.5 stable up against Linux 5.6-rc1 on a few of the systems tested so far while more results are in-progress.

There is experimental work pending that plumbs support into MEMFD for creating "secret" memory areas. This secret memory support would then be exposed to user-space for different use-cases.

While there are a lot of new end-user features with Linux 5.6, there are also some changes not yet mainlined. Here are six that come to mind as missing out on the Linux 5.6 merge window.

Linus Torvalds has just tagged Linux 5.6-rc1 as the first test kernel of the forthcoming Linux 5.6. This is going to be a jam-packed big update debuting as stable at the end of March or early April.

As first to write about yesterday, Linux 5.6 Arm platform changes now support the original Amazon Echo. While this allows the first-generation Amazon Echo to run with a mainline Linux kernel and is exciting for hobbyists, it's not really practical at this stage or even in the long-run.

For those using GNU Make in particular as their build system, the parallel build times are about to be a lot faster beginning with Linux 5.6 for large core count systems. This landing just after the AMD Threadripper 3990X 64-core / 128-thread CPU launch is one example of systems to benefit from this kernel change when compiling a lot of code and making use of many GNU Make jobs.

Last week the main set of kernel graphics driver improvements were merged while today is an interesting secondary batch of changes for the in-development Linux 5.6 kernel.

The IOMMU changes have been sent in for the ongoing Linux 5.6 kernel merge window.

Not yet mainlined in the Linux kernel but currently queued as part of the x86/cpu changes for next round is the ability for the kernel to detect split locks and either warn the offending applications or kill the processes.

Following last week's release of Linux 5.5, Con Kolivas is out today with his latest "CK" patch-set and MuQSS scheduler for this new kernel version.

The random changes have been sent in for Linux 5.6 that yield /dev/random behavioral changes and a new random flag.

While not as exciting as the USB4 support and staging code lightening for these areas managed by Linux's second in command Greg Kroah-Hartman, he also sent out the char/misc updates this week with other hardware support improvements.

In addition to the new openat2() system call in Linux 5.6, pidfd_getfd() has landed with growing interest from many different parties for what will be an increasingly used syscall moving forward.

The Direct Rendering Manager (DRM) kernel driver updates were sent in today for Linux 5.6 with plenty of fun features in tow.

With Linux 5.6 the staging area has seen new functionality but thanks to removing old code it ends up removing a fair number of lines of code from the kernel.

On top of all the spectacular work coming with Linux 5.6, here is another big improvement that went under my radar until today: Linux 5.6 is slated to be the first mainline kernel ready for 32-bit systems to run past the Year 2038!

Since the stable release of Linux 5.5 this weekend I have been carrying out benchmarks for looking at how the performance of this newly-minted kernel compares to older releases. Here are benchmark results of Linux 5.3 vs. 5.4 vs. 5.5 with an AMD Ryzen Threadripper 3970X but the results are similar to other HEDT and lower-end systems we've tested thus far.

A new system call added to the very feature rich Linux 5.6 kernel is openat2() for more extensible behavior compared to the existing openat() functionality.

Intel's Andy Shevchenko sent in the x86 platform driver updates on Monday for the newly opened Linux 5.6 merge window. There is the never-ending work on dealing with quirky Windows-focused laptops to adding new Intel hardware support and other additions.

With LLVM Clang 9.0 and Linux 5.3 together it became possible to build the mainline Linux kernel with this non-GCC compiler. The x86_64 Linux kernel Clang-based kernel builds has continued to improve through newer kernel releases. This follows the mainline AArch64 (64-bit ARM) Linux kernel mainline build by Clang too, which has been of much interest by different hardware/software vendors. There hasn't been much Clang'ing kernel efforts for other architectures, but it turns out with Clang 10 and Linux 5.6 will be another working combination, this time for IBM s390.

The Time Namespace, which was originally proposed back in 2018 for allowing per-namespace offsets to the system clocks, has finally entered the mainline kernel in early 2020 with the in-development Linux 5.6 kernel.

After last week looking at the AMD/Intel/NVIDIA contributions to the mainline Linux kernel over the past number of years, there were reader requests for seeing how some of the top distributions compare namely Red Hat, SUSE, and Canonical.

The EFI kernel code has seen a variety of clean-ups and low-level improvements to it for the Linux 5.6 cycle.

Fresh off the Linux 5.5 release, the Free Software Foundation Latin America crew has debuted their GNU Linux-libre 5.5 downstream that continues to be focused on deblobbing the kernel of drivers requiring proprietary firmware and stripping out other code/functionality that is contingent upon non-free software bits and removing the ability to load closed-source kernel modules.

Following the Linux 5.5 kernel release one of the first pull requests sent in is for the hardware monitoring "HWMON" subsystem updates. Dominating the HWMON interest this cycle is a long overdue SATA temperature monitoring driver and vastly improving the k10temp driver for AMD Zen desktop and server CPUs.

Linus Torvalds has just released Linux 5.5 as stable.

Linux 5.5 is likely to be released later today and with that are many new features. But as soon as 5.5 is released it marks the opening of the Linux 5.6 merge window and this next kernel has us particularly exciting... It's certainly shaping up to be one of the most exciting kernel cycles in recent times with many blockbuster features and improvements.

Everything is aligning that the Linux 5.5 kernel is likely to be released this coming Sunday rather than being pushed off for another week of testing.