OpenBSD 7.9 Released with Support for 255 CPU Cores and WiFi 6

OpenBSD 7.9 was released today, increasing the maximum supported CPU cores on amd64 systems from 64 to 255 due to xAPIC limitations pending better x2APIC support ^{[1, 2]}. This enables OpenBSD to scale on high-core-count processors more effectively.

The update includes initial support for 802.11ax, commonly known as WiFi 6, in its wireless stack ^[1]. This addition aims to improve wireless performance and compatibility on modern networks.

OpenBSD 7.9 also introduces delayed hibernation on amd64 laptops, allowing devices to briefly wake before entering hibernation. This feature improves power management and system responsiveness ^{[1, 3, 2]}.

The CPU scheduler has been enhanced, particularly for systems with heterogeneous or complex core configurations, offering better performance and efficiency ^{[1, 3, 2]}.

New hardware support includes the Intel ICE Ethernet driver for ARM64 platforms, expanding OpenBSD's compatibility with newer ARM devices ^[1]. Fixes were applied to the AMDGPU graphics driver and to address floating point state leakage issues on AMD Zen 1 CPUs ^[1].

On the software side, OpenBSD 7.9 adds a new system call, __pledge_open(), which grants special permissions to C library calls, potentially improving security and functionality ^[3]. The sysupgrade utility now manages low disk space on /usr partitions more gracefully, reducing upgrade failures due to storage constraints ^[2].

Multimedia support has been enhanced by adding VA-API and Widevine support to OpenBSD’s Chromium port, enabling better video decoding and DRM capabilities ^[2]. OpenBSD 7.9 can now run as a guest under the Apple M-series Mac hypervisor, improving virtualization support for Apple Silicon machines ^[2].

The release also includes initial low-level support for the FUSE API, widening the range of filesystem options usable on OpenBSD ^[2]. Finally, new versions of LibreSSL and OpenSSH were incorporated, keeping cryptographic and secure shell tools up to date ^[2].

The official changelog detailing these improvements was announced alongside the release today ^[3].