The Linux kernel's ChaCha symmetric stream cipher code has long had an AVX-512 optimized code path but it was catering to the early generations of Intel CPUs with AVX-512 (Skylake) that suffered from down-clocking under use. But now slated for arrival with Linux 7.5 is tuning the code to perform better on today's AVX-512 Intel and AMD processors that don't suffer from this limitation. In turn the ChaCha performance is as much as 99% faster with current-generation AMD Zen 5 processors...