Improvements to the Linux kernel's AES-GCM Galois/Counter Mode crypto block cipher code will yield up to 74% faster performance for AMD Zen 3 processors with the Linux 6.19 kernel in the new year.

For AES-GCM crypto use within TLS, IPsec, WiFi WPA3, HTTP/3, SSH, and other purposes there is much faster performance coming for AVX2 capable processors thanks to a new optimized code path for CPUs lacking AVX-512, like is found with AMD Zen 4 and newer.

For CPUs with VAES and AVX2 instruction support, such as AMD Zen 3, there is said to be up to 74% better performance with this new code written by Google engineer Eric Biggers. Over the years Eric Biggers has been responsible for [1]many exciting Linux kernel crypto performance optimizations from writing AVX-512/AVX10 code paths to other optimizations.

Biggers explained on the recent [2]patch series :

"This patchset replaces the 256-bit vector implementation of AES-GCM for x86_64 with one that requires AVX2 rather than AVX512. This greatly improves AES-GCM performance on CPUs that have VAES but not AVX512, for example by up to 74% on AMD Zen 3.

This patchset also renames the 512-bit vector implementation of AES-GCM for x86_64 to be named after AVX512 rather than AVX10/512, then adds some additional optimizations to it."

The patches were queued this week into his [3]libcrypto-next Git branch and expressed his intentions on having this code merged for Linux 6.19.

Benchmarks shown on [4]this patch are showing some nice gains for AMD Zen 3 such as with EPYC Milan and other processors.



[1] https://www.phoronix.com/search/Eric+Biggers

[2] https://lore.kernel.org/lkml/20251002023117.37504-1-ebiggers@kernel.org/

[3] https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=libcrypto-next

[4] https://lore.kernel.org/lkml/20251002023117.37504-2-ebiggers@kernel.org/