Meaning of sockets and cores

[pixel24]

Hi@all,

I am trying to optimise my PVE and distribute the resources optimally.

I have a Supermicro server board with two ntel(R) Xeon(R) Silver 4114 CPU @ 2.20GHz. In PVE it is displayed like this:




Does socket mean a physical processor socket? In addition, 40 cores are displayed, but the CPUs don't have that many "real" cores. At least that's what I think?

Can someone shed some light on this?

with best
pixel24

 

[RolandK]

>Does socket mean a physical processor socket?
yes

>40 cores are displayed, but the CPUs don't have that many "real" cores.

xeon 4114 has 10 cores and 20 threads and with two sockets that should be 2x20 Threads, so the operating system "sees" 40 CPUs' . have a look at /proc/cpuinfo in linux

 

[pixel24]

have a look at /proc/cpuinfo in linux

yes, that's where I got the info

Is it better to give a VM two sockets and correspondingly many cores or better one socket and more cores from this socket?

In other words, the same number of cores in total. The only question is whether it is better to distribute them over two sockets or to bind them to one?

 

[matiaspecchia]

yes, that's where I got the info

Is it better to give a VM two sockets and correspondingly many cores or better one socket and more cores from this socket?

In other words, the same number of cores in total. The only question is whether it is better to distribute them over two sockets or to bind them to one?

From the documentation:
10.2.5. Qemu/KVM Virtual Machines - Virtual Machines Settings - CPU

10.2.5. CPU​

A CPU socket is a physical slot on a PC motherboard where you can plug a CPU. This CPU can then contain one or many cores, which are independent processing units. Whether you have a single CPU socket with 4 cores, or two CPU sockets with two cores is mostly irrelevant from a performance point of view. However some software licenses depend on the number of sockets a machine has, in that case it makes sense to set the number of sockets to what the license allows you.