Intel AMX Patches For The Kernel Posted A 10th Time, But To Miss Out On Linux 5.15

Going back to June of last year there has been work on Intel bringing up Advanced Matrix Extension (AMX) that will debut with next-gen Xeon "Sapphire Rapids" processors as a new programming paradigm. Over the past year they have published patches for the Linux kernel and open-source toolchains with GCC and LLVM Clang. One year later, the AMX kernel patches are up to their tenth revision but will miss out on the imminent Linux 5.15 merge window.

Intel open-source engineers have been working on a set of more than two dozen patches around AMX handling for the Linux kernel. Among the kernel work involved is that a new system call is needed for applications to actually request feature access to Advanced Matrix Extensions, handling for applications without AMX permissions, and other changes.

Sent out on Wednesday were the tenth revision of these AMX kernel patches that have some code simplification, improved/updated code comments, and a variety of other low-level code churn. The prior "v9" patches were sent out about one month ago.

Those interested in the kernel-side patches around Intel AMX can see the v10 patches.

However, given the timing of these patches and some aspects appearing to not be yet firmly settled and the patches needing to undergo further review, the AMX support isn't likely to make it for Linux 5.15. The 5.15 kernel cycle is expected to begin next week unless delayed by one week, but even still it's so close to the merge window that it's very unlikely it will land.

Hopefully though these AMX patches will get squared away in time for the Linux 5.16 cycle... Xeon Sapphire Rapids is currently expected to ramp up in Q2'2022 so getting the code mainlined in time for spring 2022 Linux distributions like Ubuntu 22.04 LTS will be important for its initial adoption.

On the compiler toolchain side there is initial bits in GCC 11 along with GNU Binutils 2.36 and early portions in LLVM Clang 13.