2vCPU vs 4vCPU/CPU limiting

[jg27]

We currently have a lite CAD environment running AutoDesk products, CREO, and some lite abaqus.  The VMs are configured with the below:

4vcpus w/ 8Ghz limit

16GBs RAM(reserved)

M10-2B profile vGPU profile

We're implementing this limit because a higher portion of our organization controls our antivirus and from time to time it becomes a runaway process and will eat all of the CPU available.  The physical CPU on the host runs at 2.7Ghz, in a perfect world, should each core of the 4 core vCPU match that limit(2.7x4=10.8Ghz)? my understanding is that each core can run at 2Ghz  since we have 8Ghz set as the limit.  Is that true?  We're seeing some spikes in CPU ready time when users open larger/more complex models in Creo/Autodesk, but it seems to stabilize after the drawing is opening..  Increasing the CPU limit removes the ready time completely.

Would it also be more beneficial to have 2vcpus running with the same limit(8Ghz), or a limit that matches physical hardware(5.4Ghz), assuming that Creo/Autodesk are not utilizing all 4 cores?

Physical to vCPU ratio is about 1.5vcpu to 1 physical CPU across the cluster.

Any help/information is greatly appropriated.

[daphnissov]

Using CPU limits in this case is going to give you nothing but trouble as you are now experiencing firsthand. If the reason you're implementing them is due to antivirus, then I would suggest correcting the problem at its source and not working around it by using CPU limits because 1) it impacts everything and 2) they're commonly forgotten about and only re-discovered upon troubleshooting issues created by them later down the road.

[jg27]

I completely agree with the above, unfortunately we don't have any control over our antivirus and we're at their mercy to come up with a workable solution for this.  So far they've come up with nothing and its been at least a year.  The problem doesn't happen as long as we refresh our VMs on a set schedule,but it still has the potential to happen.  

Even with limits performance is good minus the spikes i see during higher usage. 

[daphnissov · Accepted solution]

And with those limits in place there's nothing you can do during those peaks. You'll just have to settle for reduced performance as long as you want to put ankle irons on your VMs.