virtualbox.org

The server is used for C++ compilations, some extensive i/o operations and using all possible cores is nice / must have. It works nice directly but ...

I would like to have one layer in between and am willing to give away some of performances. I used to work fine when there was only one CPU. I could make use of all cores -> threads (14 -> 28) when I had only one CPU. Now I have real 28 cores (56 threads), but can only give 28 cores + 2 (?!) to the 64bit Xenial guest. I have to check bios if there is something to adjust in case of 2 cpu ... perhaps enabling VT per cpu or something stupid?

Everything looks fine: What is explanation behind this? I am using latest version from official repository and stock Ubuntu Xenial 64bit server with some basic desktop ...

You may also be interested in the following CPU Cores versus threads

Perryg wrote:You may also be interested in the following ...

Thank you. That explain something, but not why my processor count is 1-32(!), with 28 as last number in the green while it should be (?) 1-56 with 28 as last number in the green.

For that answer you would need to ask the DEVs ( irc or the dev mailing list ) but assigning more cores than is available will cause some really nasty results. Some are an annoyance and others are critical. Also with each core added there is an overhead that you must account for.