The top three Linux 6.9 kernel upgrades

Linus Torvalds was happy this week. He declared, “Linux 6.9 is now out, and … the whole release has felt pretty normal.” Mr. Linux continued, “The changes [are] mostly being dominated by some driver updates (GPU and networking being the big ones).” So, what does the latest Linux kernel mean for us? Here are my thoughts on the most significant changes. 

First, there have been many CPU improvements. In alphabetical order, by vendor:

Linux 6.9 introduces support for AMD Preferred Core. This means Linux 6.9-based systems can prioritize high-performance cores for demanding tasks. The net effect should be to boost overall system efficiency. Additionally, it includes the FRU Memory Poison Manager. This isn’t as dramatic as it sounds. It just helps manage error records on persistent storage. This release also includes support for AMD Secure Nested Paging (SNP) for enhanced security.

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As for ARM, Linux 6.9 marks a significant milestone by introducing Rust support for the ARM64 architecture. This is one more step towards future Rust-based Linux kernel code. This release also adds support for various new ARM-based hardware, including the MediaTek MT8186-based Chromebooks. I expect we’ll see more ARM improvements in future kernel releases since Torvalds now has, he tells us, a “powerful arm64 machine (thanks to Ampere), so the last week I’ve been doing almost as many arm64 builds as I have x86-64.” 

On Intel, the 6.9 kernel now supports Intel’s Flexible Return and Event Delivery (FRED) architecture. This means that starting with the forthcoming Intel Meteor Lake CPUs, we’ll see improved performance and efficiency. There have also been improvements with the x86 CPU topology code for better hybrid CPU support. 

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Oh, and if you happen to have truly enormous amounts of RAM available to your processor — like a Terabyte or more of RAM — your boot-up times will be faster than ever before. You’ll never see that on your home PC — or if you do, I want to know where you got your machine — but for people running supercomputers or truly massive cloud applications, this will make a real difference. 

Moving along to the file systems with Flash-Friendly File System F2FS, you can expect to see better storage performance with your flash memory-based storage devices, such as SSD, eMMC, and SD cards. People using Oracle’s XFS file system will be pleased that you can now repair corrupted files without unmounting your XFS drives. 

Moving to networking, there are a host of minor improvements. What they all boil down to is faster performance across your network. Since I’ve moved to Gigabit plus Internet and local area network (LAN) speeds, I’m particularly interested in the improvements to Linux’s Energy Efficient Ethernet code. This will improve my  2.5 Gigabit Ethernet links.

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With these enhancements, Linux 6.9 provides improved file system performance, better compression, and more efficient storage utilization. Simultaneously it’s also delivering better networking support, increased throughput, and optimizations for various wired and wireless devices. 

Looking ahead, as Torvalds said, “This means that tomorrow, the merge window for 6.10 opens.” An operating system designer’s work is never done.