OpenBSD 7.9: Wi-Fi 6, USB4 and 255 Core Support. Key OS Changes

Some changes relate to virtualization and power saving, while others concern low-level security mechanisms and the network subsystem. Let's break down what's new and how it works.

Task Scheduler and Work with Processors of Varying Performance

The task scheduling mechanism for hybrid processors has been completely redesigned in the kernel for amd64 and arm64 architectures. Now, you can set a sequence of flags via the hw.blockcpu sysctl variable to exclude specific core classes from the scheduler's consideration. The S flag corresponds to logical SMT cores, P to standard performance cores, E to energy-efficient cores that run 20–50% slower, and L to the most throttled core variants. The default value is SL, though an administrator can adjust it for specific workloads, for example, leaving only P and E cores to balance speed and heat output.

Additionally, the mutex locking mechanism in the kernel has been updated. Now, instead of constantly spinning a loop while waiting for a resource to be freed, threads are put to sleep, which reduces CPU load and lowers heat in multiprocessor systems. At the same time, the maximum number of cores for amd64 has been increased from 64 to 255, and you can now retrieve information about performance and energy-efficient cores via kstat.

Developers tested the new features under mixed workloads where computational and background processes run simultaneously. The scheduler has become noticeably more responsive to changes in the hw.blockcpu configuration without a reboot. This is especially important for servers and workstations with asymmetric CPUs, where uneven resource utilization had to be tolerated previously. The update makes system behavior more predictable when scaling.

In addition, developers fixed the order of processor iteration in CPU_INFO_FOREACH and added support for hw.blockcpu on arm64. Kernel performance information is now available not only inside the kernel, but also in user space, so utilities can more accurately account for differences between core types. At the same time, these changes do not break old configurations and do not require separate configuration after the update.

Delayed hibernation and device power management

OpenBSD 7.9 introduces a delayed hibernation mechanism configured via machdep.hibernatedelay. First, the system enters regular suspend-to-RAM, where the memory contents stay in RAM and the device can be woken up quickly. If the computer remains inactive for a long time, the kernel automatically switches it to full hibernation, saving the state to disk. This approach allows the battery not to run completely flat during long idle periods, while maintaining fast wake-up in the first few hours after entering sleep.

PCI drivers now automatically switch power consumption levels. In particular, the xhci driver switches the controller to low power mode and puts associated USB4 devices to sleep. These operations are transparent to the user and do not require additional settings. The changes apply not only to laptops, but also to embedded systems where every watt of power matters.

The mechanism has been tested in real-world long wait scenarios. Hibernation triggers exactly at the specified time, and wake-up remains fast thanks to saving the state in RAM at the initial stage. Developers took into account the behavior of different chipsets to avoid conflicts with ACPI.

Graphics stack, virtualization and new drivers

The drm framework and AMDGPU and Intel drivers in OpenBSD 7.9 have been synchronized with code from Linux 6.18.22, replacing the previous 6.12.50. The system now has fresher support for modern GPUs, and several old problems have also been fixed, including floating-point state leaks on Zen 1. In practice, this means fewer strange graphics glitches and more stable operation of applications with hardware acceleration.

The release adds full support for running OpenBSD as a guest system under Apple Hypervisor. arm64 builds now launch properly in macOS virtual machines on Apple Silicon computers. Additionally, a compact vmboot kernel has been added for the vmd hypervisor, which simplifies system startup after sysupgrade and removes several unnecessary steps during virtual machine boot.

OpenBSD 7.9 adds support for USB4, Cadence PCIe controllers, Qualcomm SC7280, GENI UART, Intel LPSS SPI, and the Quectel EC200A LTE modem. The Intel ICE driver now also works on arm64. The system now has better compatibility with modern laptops, mini PCs, and ARM boards. A basic FUSE API has also been added to the codebase, which is already sufficient to build and run lowntfs-3g.

Networking capabilities and wireless standards

OpenBSD 7.9 now has full support for Wi-Fi 6 (802.11ax standard). Updates to the iwx and qwx drivers improve connection stability in congested networks and help make more efficient use of the high bandwidth of modern routers. The difference is especially noticeable on laptops and compact ARM devices, where new access points previously sometimes worked unstably.

The veb virtual Ethernet Bridge now supports VLAN, making it easier to configure network segmentation in virtual environments. Automatic IPv6 configuration via SLAAC is now enabled by default, so in most cases the system brings up the network on its own without manual config file editing.

Developers have also updated several network stack components related to routing and packet processing. Such changes are rarely noticeable immediately after system installation, but they usually have the biggest impact on network stability under high load.

Boot-level and system call security

On amd64 systems, OpenBSD 7.9 adds the ability to load the kernel and bsd.rd installation images directly from an EFI partition. Now the bootloader, installer, and related files can be stored in the standard EFI System Partition without separate boot partitions or non-standard disk partitioning. For modern laptops and mini PCs with UEFI, this simplifies system installation, recovery from failures, and multi-boot setup alongside Linux or Windows.

In libc, a new system call __pledge_open has appeared. It is needed for programs that, after enabling pledge and unveil restrictions, still require access to certain system files. For example, to /dev/random, the time zone database, or other resources without which some system utilities cannot function properly. At the same time, files are opened only in read mode - writing, changing attributes, and passing descriptors remain prohibited.

OpenBSD 7.9 also updated OpenSSH to 10.3, LibreSSL to 4.3, and OpenBGPD to 9.1. In OpenSSH, several compatibility issues were fixed and cryptographic algorithms were updated. LibreSSL received fixes in TLS components and certificate processing, while OpenBGPD improved routing and BGP session handling.

Ports and Application Updates

The number of ports for amd64 in OpenBSD 7.9 has grown to 13,044, for aarch64 to 12,883, and for i386 to 10,631. The repositories have been updated with a large amount of popular software, including Asterisk 22.9.0, Audacity 3.7.7, CMake 4.2.3, Chromium 147, Emacs 30.2, FFmpeg 8.0.1, and GCC 15.2.0. The system also includes fresh versions of GNOME 49, KDE Plasma 6.6.4, Firefox 150, Thunderbird 140, Go 1.26.2, Rust 1.94.1, Python 3.13.13, PostgreSQL 18.3, and Node.js 22.22.2.

Xfce has been updated to version 4.20.0, and Wayland 1.24.0 is now shipped with the Labwc, Mango, Niri, Sway, and Wayfire composite servers. LibreOffice has reached version 26.2.2.2, and SQLite has reached 3.51.3. The Xenocara graphics subsystem is still based on X.Org 7.7 but includes xserver 21.1.21 and fresh Mesa 25.0.7 patches.

For OpenBSD, such updates are particularly important because ports remain one of the main ways to obtain modern user software without manual compilation and third-party repositories. At the same time, the project continues to support multiple architectures, including arm64, where the number of available packages has almost caught up with amd64.

OpenBSD 7.9 is unlikely to become a mass system for everyone in the foreseeable future. But the project isn't even trying to play by these rules. The new release rather shows something else: developers continue calmly and consistently to bring the system to a state where even complex low-level mechanisms remain relatively transparent and predictable. Support for hybrid processors, Wi-Fi 6, USB4, and Apple Silicon shows that OpenBSD is gradually adapting to modern hardware, without turning into an overloaded platform with dozens of extra layers of abstraction.