virtualbox.org

hi,

This is the bug of dual sockets processors motherboard. I have a Windows 8.1 workstation with 14 cores(28 threads) per socket processor x 2 = 28 cores(56 threads). But the VB(Ubuntu) showing maximum 32 cpus and allowed only 28 cpus selection. In the Task Manager, i can see that only 28 threads are running max. Which mean VB only detect one socket processor. This is the same bug that reported here: viewtopic.php?f=7&t=60308
Recent version:
5.0.10

Also tried:
5.0.2
5.0.8
4.3.8
4.3.8 RC1
4.3.10

I hope the bug can be fix very soon. Thanks.

By the way, is there any previous version can be use Dual socket processors? Please suggest, thanks guys.

Regards,

Rex

14-core processors? Wow.
My dual-six-core Xeon shows 12 cores available too, but I don't think Virtualbox is skipping a socket.
It's likely the "X 2" thing. Virtualbox doesn't count hyperthreading. So you'll only have the physical cores available in Virtualbox. It isn't a bug. It was explained recently on the forum that if two threads that are working on different tasks at the CPU level want to get run through a hyperthreading core, the core will let both through at the same time, because they live in different parts of the one core. But threads running an OS are too similar, and the overhead would slow down the guests, so the developers have not implemented hyperthreading.
FWIW, 4.3 is where the GUI stops showing the hyperthreaded count. 4.2 & earlier count the hyperthreaded cores in the slider in the GUI, but I don't know if that many cores get presented to the guest or not, or if the code is there in Virtualbox to allow all of them to be used in the guest.

scottgus1 wrote:14-core processors? Wow.
My dual-six-core Xeon shows 12 cores available too, but I don't think Virtualbox is skipping a socket.
It's likely the "X 2" thing. Virtualbox doesn't count hyperthreading. So you'll only have the physical cores available in Virtualbox. It isn't a bug. It was explained recently on the forum that if two threads that are working on different tasks at the CPU level want to get run through a hyperthreading core, the core will let both through at the same time, because they live in different parts of the one core. But threads running an OS are too similar, and the overhead would slow down the guests, so the developers have not implemented hyperthreading.
FWIW, 4.3 is where the GUI stops showing the hyperthreaded count. 4.2 & earlier count the hyperthreaded cores in the slider in the GUI, but I don't know if that many cores get presented to the guest or not, or if the code is there in Virtualbox to allow all of them to be used in the guest.

Thank you so much scott, i'll try version 4.2 to find out.