Where are hyperthreaded cores?

[Mihies]

I see that Workstation supports up to 4 cores per CPU. Now I wonder why it won't use hyperthreaded cores (think Core i7 which has 4+4).

Because the 4 cores limitation?

[TobiasKracht]

It supports up to 4 v(!!!)CPU per Vm.

StarWind Software R&D

[Mihies]

Hi Tobias,

Yes, I know but it doesn't help if one has a single CPU with 4+4 cores.

[TobiasKracht]

http://www.vmware.com/pdf/ws7_manual.pdf - page 366 (or close to it)

StarWind Software R&D

[Mihies]

Good link. Looks like it is because 4 cores/CPU limitation not because the other 4 cores are hyperthreaded.

[continuum]

yep - by the way - you sure would not want to run a VM with 8 virtual CPUs - the expected performance would be horrible slow




___________________________________

VMX-parameters- VMware-liveCD - VM-Sickbay

[Mihies]

Why would be slow on Core i7? It natively supports 8 cores (ok, 4 of those are hyperthreaded but nevertheless). I'd expect if I run a single VM on all of 8 cores it would run comparable to host OS, wouldn't it?

[continuum]

nope - the more virtual CPus a VM uses the slower it usually is - yes I know this is not what you would expect because in real world usually more is more. In virtual world less is more

If a VM uses 8 cores it can only work if the host OS at the same time does not uses any core itself.

So a VM with 8 cores spends most of the time with simply waiting ...

If you are interested in the background read some documents about scheduling cores - you will find several good posts with the search function




___________________________________

VMX-parameters- VMware-liveCD - VM-Sickbay