Earlier this month Intel engineers posted their initial Linux kernel enablement around x86 User Interrupts with this feature premiering with Xeon "Sapphire Rapids" CPUs.
As implied by the name, the User Interrupt functionality allows for interrupts to bypass the kernel for more efficient, low-latency, low-utilization interrupts being received by other user-space tasks. Intel talked more about User Interrupts this week at LPC2021. Sohil Mehta of Intel presented at Linux Plumbers Conference on their recently-posted kernel patches for enabling x86 User Interrupts. User Interrupts for delivering events directly to user-space should be a big win for improving Linux inter-process communication and I/O events. The patches currently out are focused on user-to-user IPC while coming soon will be patches for User Interrupts support for going from kernel-to-user followed by allowing User Interrupts sent from other devices directly to user-space.
User Interrupts along with other features like AMX have me very excited for Sapphire Rapids next year. As noted earlier this month and reiterated during this presentation, User Interrupts can be up to 9x faster for lower IPC communication latency with Sapphire Rapids. Those wanting to learn more about this exciting Intel addition coming to their next-generation Xeon Scalable processors and pending kernel support can see the presentation below along with this slide deck.