[Users] cores and threads

[David N Bradley]

Your message appeared before I could send my own.

This could explain some things I was not aware of.

Hope I did not disrupt the meeting, as usual my audio had an echo.

I usually copy vara.hamradio.net.ini  to generic.ini and proceed.

On 1/14/21 10:09 AM, Roland Haas wrote:
> Hello David,
>
> since "hyperthreads" is an Intel concept AMD does not always use it
> (plus there are flavors of the same concept eg on AMD's Bulldozer CPUs
> there are 4 floating point units for 8 integer units, where we tend
> to sometimes see benefits going to all 8 integer cores or at least
> will do so on clusters since even a 5% speed increase "for free" is
> worth it).
>
> Anyhow, if you can provide the output of lscpu on your system that will
> explain things.
>
> Simfactory uses the "Core(s) per socket" and "Socket(s)" values to
> compute the number of physical cores and hence the number of threads it
> allows. The hyperthreads (or equivalent) would be "Thread(s) per core".
>
> Note that Wikipedia:
>
> https://en.wikipedia.org/wiki/List_of_AMD_FX_microprocessors#Bulldozer_Core_(Zambezi,_32_nm)
>
> does list your processors as 4 cores and 8 threads.
>
> I don't have access to your CPU but eg on a the Blue Waters login nodes
> (Instanbul/Bulldozer, AMD Opteron(TM) Processor 6276) the output is:
>
> Architecture:        x86_64
> CPU op-mode(s):      32-bit, 64-bit
> Byte Order:          Little Endian
> CPU(s):              64
> On-line CPU(s) list: 0-63
> Thread(s) per core:  2
> Core(s) per socket:  8
> Socket(s):           4
> NUMA node(s):        8
> Vendor ID:           AuthenticAMD
> CPU family:          21
> Model:               1
> Model name:          AMD Opteron(TM) Processor 6276
>
> Yours,
> Roland
>