Hey,

 

I have a CPU with 4 cores/8 threads.

UNRAID shows thread pairing as 0-4, 1-5, 2-6, 3-7

 

Does this mean I need to keep these pairings when creating a VM?

Example if i wanted 2 cores/4 threads for a VM, do I select cores 0,4 and cores 1,5 or just select cores 0,1,2,3?

 

Thanks.

 

When using CPU cores in virtualization, forget about threads, you just have cores to work with. With the work I have done with UnRaid regarding virtualization, I have not found that you need to choose specific cores for your vm however it is important to remember to leave enough resources for UnRaid itself to run the host OS. Also I doubt you will need to assign more then two cores to a VM unless you are doing something with it that is very CPU intensive. In the Windows 10 VM I have running on one of my UnRaid servers, I have simply assigned cores 0,1 to the VM and it runs fine, no issues, so no you don't have to stick with the pairings.

What command are you using for thread pairing determination?

Some tools aren't as accurate as others, especially when there is a perfectly built in means of finding thread sibling cores.

What command are you using for thread pairing determination?

Some tools aren't as accurate as others, especially when there is a perfectly built in means of finding thread sibling cores.

 

I'm using: Tools > System Devices > CPU Thread Pairings.

I don't know how accurate that is.

I actually have the very same question and I don't want to start a new thread if I don't have to.

 

My CPU is an E5-2670v3 it has 12 cores 24 threads. I want to setup 5 dockers and have 1 VM for Windows 10. How many cores should I leave for UnRaid to run properly and stable. One of the dockers is Plex and I have 2 trans-coding streams max. The rest I want to allocate towards the Windows VM since I am developer and design student and use a lot of programs at once.

 

 

I actually have the very same question and I don't want to start a new thread if I don't have to.

 

My CPU is an E5-2670v3 it has 12 cores 24 threads. I want to setup 5 dockers and have 1 VM for Windows 10. How many cores should I leave for UnRaid to run properly and stable. One of the dockers is Plex and I have 2 trans-coding streams max. The rest I want to allocate towards the Windows VM since I am developer and design student and use a lot of programs at once.

 

As a general rule of thumb, you need ~2000 passmark points per 1080p transcode.  Your processor has a single thread passmark score of 1694.  Assuming your other docker instances aren't CPU intensive, I'd leave 4 threads for running unRaid.

I actually have the very same question and I don't want to start a new thread if I don't have to.

 

My CPU is an E5-2670v3 it has 12 cores 24 threads. I want to setup 5 dockers and have 1 VM for Windows 10. How many cores should I leave for UnRaid to run properly and stable. One of the dockers is Plex and I have 2 trans-coding streams max. The rest I want to allocate towards the Windows VM since I am developer and design student and use a lot of programs at once.

 

As a general rule of thumb, you need ~2000 passmark points per 1080p transcode.  Your processor has a single thread passmark score of 1694.  Assuming your other docker instances aren't CPU intensive, I'd leave 4 threads for running unRaid.

 

Where did you find the single thread passmark information for my cpu? I only found the Passmark cpu benchmark list which lists my cpu at a passmark score of 16686.

Where did you find the single thread passmark information for my cpu? I only found the Passmark cpu benchmark list which lists my cpu at a passmark score of 16686.

 

You were probably looking at the right site: https://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+E5-2670+v3+%40+2.30GHz

 

Below the Passmark score you'll see the "Single Thread Rating".

What command are you using for thread pairing determination?

Some tools aren't as accurate as others, especially when there is a perfectly built in means of finding thread sibling cores.

 

I believe LT is now using this to determine (from the previous thread):

I took a look at /proc/cpuinfo, where there is a "core id" field for each logical processor.  So for my Xeon E3-1240 v3 it looks like these are my pairs:

 

0,4
1,5
2,6
3,7

 

And that matches what I see in these files:

  /sys/devices/system/cpu/cpu0/topology/thread_siblings_list
  /sys/devices/system/cpu/cpu1/topology/thread_siblings_list
  /sys/devices/system/cpu/cpu2/topology/thread_siblings_list
  /sys/devices/system/cpu/cpu3/topology/thread_siblings_list
  etc.

 

Does this seem like it is on the right track?

 

Seems like this should give you the list of siblings:

 

cat /sys/devices/system/cpu/*/topology/thread_siblings_list | sort -u

Beautiful...  Honestly didn't know that existed. Must be new. Well, we have added that under the system devices page for a future release.  Awesome find!!

 

It is recommended to pair the hyperthreaded core to the logical core, as they share the same cache.

This should also cut down on latency vs having the HT core doing something else (VM/process).

Where did you find the single thread passmark information for my cpu? I only found the Passmark cpu benchmark list which lists my cpu at a passmark score of 16686.

 

You were probably looking at the right site: https://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+E5-2670+v3+%40+2.30GHz

 

Below the Passmark score you'll see the "Single Thread Rating".

 

Thanks I just overlooked it.