March 11, 2019

New Linux Kernel: The Big 5.0


The latest Linux kernel is loaded with new features.

Linus Torvalds at last made the jump with the recent release of kernel 5.0. Although Linus likes to say that his only reason to move on to the next integer is when he runs out of fingers and toes with which to count the fractional part of the version number, the truth is this kernel is pretty loaded with new features.

On the network front, apart from improvements to drivers like that of the Realtek R8169, 5.0 will come with better network performance. Network performance has been down for the last year or so because of Spectre V2. The bug forced kernel developers to introduce something called a Retpoline (short for "RETurn tramPOLINE") to mitigate its effect. The changes introduced in kernel 5.0 "[...] Overall [give a greater than] 10% performance improvement for UDP GRO benchmark and smaller but measurable [improvements] for TCP syn flood" according to developer Paolo Abeni.

What hasn't made the cut yet is the much anticipated integration of WireGuard. Wireguard is a VPN protocol that is allegedly faster, more versatile and safer than the ones currently supported by the kernel. Wireguard is easy to implement, uses state of the art encryption, and is capable of maintaining the network link to the VPN up even if the user switches to a different WiFi network or changes from WiFi to a wired connection.

An ongoing task is the work going into preparing for the Y2038 problem. In case you have never heard of this, UNIX and UNIX-like systems (including Linux) have clocks that count from January the 1st, 1970. The amount of seconds from that date onwards is stored in a signed 32-bit variable called time_t. The variable is signed because, you know, there are some programs that need to show dates before the 70s.

At the moment of writing we are already somewhere in the 01011100 01110010 10010000 10111010 region and the clock is literally ticking. On January 19th 2038, at 3:14:07 in the morning, the clock will reach 01111111 11111111 11111111 11111111. One second later, time_t will overflow, changing the sign of your clock and making your system believe, along with millions of devices and servers worldwide, that we are back in 1901.

Then... well, the usual: planes will fall from the sky, nuclear power stations will melt down, and toasters will explode, rendering the world breakfastless. That is, of course, unless the brave kernel developers don't come up with a solution in the meantime. Then again, they made the Wii controller work in Linux, what could they not achieve?

More stuff to look forward to in Linux kernel 5.0

  • Native support for FreeSync/VRR of AMD GPUs means that now your smart monitor and your video card can sync up their frame rates and you won't see any more tearing artifacts when playing a busy game or watching an action movie.
  • Linux now has native support for and boosted the performance of the Adiantum filesystem encryption. This encryption system is used in low-powered devices built around ARM Cortex-A7 or lower -- think mid- to low-end phones and many SBCs.
  • Talking of SBCs, the touch screen for the Raspberry Pi has at last been mainlined, and Btrfs now supports swap files.

As always, you can find more information about Linux 5.0 by reading Linus's announcement on the Linux Kernel mailing list, checking out the in-depth articles at Phoronix and by reading the Kernel Newbies report.

Learn more about Linux through the free "Introduction to Linux" course from The Linux Foundation and edX.

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