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NonComposMentis
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VMware Workstation virtual cores > num threads offered by microprocessor?

Greetings --

Is it possible to run multiple VMs on Workstation such that the total number of virtual cores adds up to more that the number of real threads offered by your microprocessor?

I am building a new PC on which I intend to run the latest VMware Workstation.  My problem is that all of the 7th generation processors are limited to 4 cores (8 threads).  In the past I have had 12 threads, and was careful to keep the total number of virtual cores of my running VMs less than that.  This will not be possible with the new PC with 8 threads unless I rebuild the VMs also, which I was hoping to avoid.  I have seen no literature saying you must have enough microprocessor threads to cover your VMs, but then VMware also *recommends* 4 GB RAM, so I take scant comfort in that.

So what do you say? Am I being unduly paranoid?

Thanks,

Gary

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NonComposMentis
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I now have my system set up with a 6 core (12 thread) microprocessor, which I got just to be safe. However, I can also report that I have been able to load several VMs with a total virtual core count of 20, and they work just fine.  Furthermore, I had an issue with "Intel Turbo Boost Max Technology" in which all processing was being assigned to a single host thread.  The three VMs I had loaded at the time still worked, albeit at a snail's pace.  This seems sufficient disproof of the hypothesis that there must be a host thread for every virtual core.

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bluefirestorm
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Unless you are planning to run multiple VMs that will constantly use up all processor cycles such as compiling programs, performing intensive computing, etc, the number of total virtual CPUs running exceeding the total core/thread count of the CPU should not be such an issue. Most modern OS are generally idle anyway. If you think back even to the earliest releases of Workstation, multi-core processor, let alone multi-thread CPUs were not even common.

As to memory, again it depends on how much you want to allocate to each VM how much will be in use by each VM.

There is a preference setting that can be seen in the documentation.

https://pubs.vmware.com/workstation-12/topic/com.vmware.ICbase/PDF/workstation-pro-12-user-guide.pdf...

I have pasted here a screenshot of that documentation page so that it is easier to visualise.

pastedImage_1.png

NonComposMentis
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I now have my system set up with a 6 core (12 thread) microprocessor, which I got just to be safe. However, I can also report that I have been able to load several VMs with a total virtual core count of 20, and they work just fine.  Furthermore, I had an issue with "Intel Turbo Boost Max Technology" in which all processing was being assigned to a single host thread.  The three VMs I had loaded at the time still worked, albeit at a snail's pace.  This seems sufficient disproof of the hypothesis that there must be a host thread for every virtual core.

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ksc
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As long as VMs are generally idle, total virtual cores exceeding total physical cores - across multiple VMs - is fine. Things will eventually slow down, but only if total CPU usage gets too high.

We don't allow any single VM to exceed physical cores. Our software can do it, but the result does not meet VMware's standards - in fact, it generally goes pathological very fast.

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