151
Hardware and Performance / Re: Hyperthreading is vailable in 19.1.x?
« on: July 12, 2019, 11:09:55 am »
@mimugmail: sorry, but I think it does make sense to raise this topic in the hardware section for opnsense.
@tillsense: What you said, is a little bit unclear to me. I do know what Intel HTT does. I do understand, that HTT is a vendor-branding name for the concept called Symmetric Multithreading, SMT. What I dont really understand, how AMD implemented their own version of SMT.
Does that mean that 1 single core of the GX-412TC can execute 2 threads in parallel, but its not called as Hyperthreading, so the logical CPU count actually equals the physical CPU core count, and the SMT magic is hidden from the OS schedulers eyes?
I am curious whether machdep.hyperthreading_allowed="0" should be set, if HTT is not supported by this CPU, but multithreading is?
Update: according to wikipedia, Jaguar class CPUs (like the GX-412TC) do not feature Clustered MultiThread (CMT), the type of SMT we are speculating as incorrectly marked as HTT capability
Jaguar does not feature clustered multi-thread (CMT), meaning that execution resources are not shared between cores
Source:
https://en.m.wikipedia.org/wiki/Jaguar_(microarchitecture)
@tillsense: What you said, is a little bit unclear to me. I do know what Intel HTT does. I do understand, that HTT is a vendor-branding name for the concept called Symmetric Multithreading, SMT. What I dont really understand, how AMD implemented their own version of SMT.
Does that mean that 1 single core of the GX-412TC can execute 2 threads in parallel, but its not called as Hyperthreading, so the logical CPU count actually equals the physical CPU core count, and the SMT magic is hidden from the OS schedulers eyes?
I am curious whether machdep.hyperthreading_allowed="0" should be set, if HTT is not supported by this CPU, but multithreading is?
Update: according to wikipedia, Jaguar class CPUs (like the GX-412TC) do not feature Clustered MultiThread (CMT), the type of SMT we are speculating as incorrectly marked as HTT capability
Jaguar does not feature clustered multi-thread (CMT), meaning that execution resources are not shared between cores
Source:
https://en.m.wikipedia.org/wiki/Jaguar_(microarchitecture)