Comment by jeffbee
14 hours ago
"Intel CPUs were downclocking their frequency when using AVX-512 instructions due to excessive energy usage (and thus heat generation) which led to performance worse than when not using AVX-512 acceleration."
This is an overstatement so gross that it can be considered false. On Skylake-X, for mixed workloads that only had a few AVX-512 instructions, a net performance loss could have happened. On Ice Lake and later this statement was not true in any way. For code like ChaCha20 it was not true even on Skylake-X.
This was written in the past tense, and was true in the last decade. Only recently Intel came up with proper AVX-512
It wasn't. My comment covers the entire history of the ISA extension on Intel Xeon CPUs.
I netted huge performance wins out of AVX512 on my Skylake-X chips all the time. I'm excited about less downclocking and smarter throttling algorithms, but AVX512 was great even without them -- mostly just hampered by poor hardware availability, poor adoption in software, and some FUD.
Yeah I would have loved benchmarks across generations and vendors.