Re: Chess.com 2018 computer chess championship
Posted: Sun Sep 16, 2018 11:11 pm
CMCanavessi wrote: ↑Sun Sep 16, 2018 9:46 pm Interesting. I wonder how Intel hyperthreads compare to AMD hyperthreads. As far as I know, AMD ones are way more efficient and work way better, while Intel ones kinda suck, at least for chess. Is there some kind of study about this?
I cannot test every platform/combinations but to my knowledge, with more recent generation of chips both Intel and AMD are getting better efficiency with hyper-threads. Intel HT jumped from 30%(compared to real core) at the age of Core2-ish to about 70% performance with the latest Scalable Xeons, and AMD is doing around 60% with Ryzen 7, should be better according to the available benchmarks of their new chips.
Also note that unlike old times, now it does not matter which core(real or fake) you run your threads on, things get rearranged internally and their combined performance is reliable, it is now a non-issue if you bind all your threads to fake cores and get only hyper-threaded performance, should be easier for NUMA implementations: expect big numbers in Threads option and support Windows processor groups.
As for memory affinity, I think modern OS knows how to schedule/migrate things better enough, unless you have a really big system, nothing can break and it'd work out-of-box. Plus, CCCC runs on virtual machines, hypervisor is the overlord and whatever you do doesn't matter anyways.