Intel CPUs with P and E cores or other server CPU suggestions

[MasterOSkillio]

Hi I had been building a XCP-NG server based around an intel 12600k I had lying around but my desktop just died today and I was thinking I might grab that motherboard and CPU to replace the old desktop. I am however usure if I want to go that route and replace the server CPU I had or just replace the desktop. I am a bit lost on what direction I should go in, CPU and motherboard wise.

I come from a server setup where I had two old Xeons, I was running VMware for a long time with no issues, but I wanted to move on to something else that was more home user friendly and would use less power.

1. I want to stick with ECC ram as I will be doing some production work stuff on the server VMs, just really testing, and nothing permanent.

2. For my needs I think depending on what I can find I was thinking to be in the 128-256gb of ram area

3. The server will most likely be idle for a large part of the time, so I want to figure out what hardware I can use to put it into C states that will use the least amount of power, obviously that will reflect a lot on the motherboard and what it can do as far as C states (I had been planning to undervolt the 12600k along with c states to get idle power down even further)

4. From what I have seen in various places on the web P and E cores are not really supported yet for XCP-NG? Is it safe to assume that is changing? I believe proxmox, and VMware have moved to support them. If I use the 12600K will I have to turn off one (P or E) and use only the other?

5. I have never tried, but I am sure a modern xeon motherboard will not let me play with voltages to lower the overall power usage?

6. What does this board recommend for CPUs generally? I am going to be using this server for media so I defiantly want something that supports modern codecs like AVX.

From a budget standpoint I have the case / power supply / drives so I am really looking at CPU / Ram / motherboard, I don't mind spending a little on something nice as long as the features are there.

[Fionn]

@MasterOSkillio said in Intel CPUs with P and E cores or other server CPU suggestions:

From what I have seen in various places on the web P and E cores are not really supported yet for XCP-NG? Is it safe to assume that is changing? I believe proxmox, and VMware have moved to support them. If I use the 12600K will I have to turn off one (P or E) and use only the other?

Not sure what you mean by "support" but I'm running as of now the P+E core setup and it works just fine. Stable, performs as expected.

[gb.123]

@Fionn

Can you let me know if you can 'choose' between the P & E Cores when assigning it to the VM ? Or does it allot randomly ?

[Fionn]

@gb.123
I'm not using that feature as for the current setup this is not of any relevance, however you should check this: https://docs.xcp-ng.org/compute/#numa-affinity

via ssh those may give you what you are looking for:
xl vcpu-list
xenpm get-cpu-topology
xl info --numa

and probably you can set the core to use as:
xe vm-param-set uuid=[VM-UUID] VCPUs-params:mask=8,9,10,11,12,13,14,15`

if you define only core 3.7.9 as example (you have to know which is E or P) should do the trick.

[tjkreidl]

@MasterOSkillio Typically, C-states need to be changed in the BIOS. In some cases, it can be very helpful. I wrote a few blogs including this topic entitled "A Tale of Two Servers" but cannot readily find them on-line at the moment. Alas, Citrix has purged a lot of still relevant older content over the years.