Linux 6.15 Crypto Subsystem Delivers Faster AES-CTR For AMD Zen 5 & Other x86_64 CPUs

The cryptography subsystem updates for the in-development Linux 6.15 merge window are quite exciting with some optimizations for modern x86_64 Intel/AMD processors enticing us the most.

Merged last week were all of the crypto updates for Linux 6.15. This includes dropping the legacy compression interface, enhancing the scatterwalk API, Kerberos5 algorithms added, dropping some obsolete SIMD fallback code, adding a new “0x1134” PCI device ID in the AMD CCP driver for an unknown product, and a variety of fixes.

Most significant to end-users with these crypto updates is the new VAES-based AES-CTR optimized version for benefiting newer Intel and AMD processors. This is the patch series I wrote about back in February within New Linux Patches Yield Up To 3.3x Faster AES-CTR Performance On AMD Zen 5 CPUs. There can be some very significant performance benefits from this optimized AESNI+AVX+VAES AES-CTR code path:

This is yet another big crypto optimization that was carried out by Google engineer Eric Biggers. AMD Zen 5 processors are benefiting the most from this work. And it builds upon many other nice crypto optimizations in recent kernel versions for different algorithms to further accelerate the performance on x86_64 processors.