#avx512 — Public Fediverse posts

AVX-512's VPCOMPRESS instruction is so damn cool. For a simple array filtering problem (retain in-place only even 32-bit numbers out of a 256MiB array), it'll out-perform native C code by a factor of 10x. The C code executes at about 800MHz, while the AVX512 code executes at about 90MHz - it's just 100 times more productive with the cycles it executes.

#avx512 #vectorization

Holy shit, `VPSHLDQ` is so cool! On my laptop, the scalar `SHLD` on 64-bit GPRs is 1-3 cycles of latency. `VPSHLDQ` does the same thing (with a constant shift value, which is fine for my use case) on a 8x64-bit ZMM register with just 1 cycle of latency. I can perform the same operation 8-24 times faster!

#simd #vectorization #avx512

Double yikes in CPU vulnerabilities! Both articles are from #ServeTheHome

#Intel DOWNFALL Ultra-Scary #AVX2 and #AVX512 Side channel Attack Discovered

https://www.servethehome.com/intel-downfall-ultra-scary-avx2-and-avx-512-side-channel-attack-discovered/

New Inception Vulnerability Impacts ALL #AMD Zen CPUs Yikes

https://www.servethehome.com/new-inception-vulnerability-impacts-all-amd-zen-cpus-yikes-phantom/

#Security