Host detects wrong number of cores (half of them)

[Alex]

I've a system with 4 Opteron 6174, each of them has 12 cores so the system has a total of 48 cores.

But Vbox seems to detect just half of them, this is the relevant line on one of the client log files:

00:00:00.728345 Physical host cores: 24

I attach the full log for completeness

[aeichner]

Can you check every available directory in /sys/devices/system/cpu which looks like cpu<digit> and upload the content of the following files in each of the directories:

/sys/devices/system/cpu/cpu<digit>/topology/core_id
/sys/devices/system/cpu/cpu<digit>/topology/physical_package_id

[Alex]

attached

[Frank Mehnert]

Thank you. Actually could you attach all files from

/sys/devices/system/cpu/cpu*/topology

The file content you attached explains why VBox shows half of the physical cores -- there are only 4 different physical_package_ids with 6 core_ids per package ID. I wonder what's missing here.

[Alex]

/sys/devices/system/cpu/cpu*/topology

[Alex]

I updated the attachment with the content you requested.

Hope this helps!

[Frank Mehnert]

Just a short notice that I didn't forget this. The information indeed explains that VBox will show a wrong value but actually currently I have no idea how to correctly determine the number of physical cores from these data, need to have some more detailed looks.

[Alex]

Thanks for the update.

If I can provider other useful infos please do not esitate to ask.

[Berto]

I've got the same problem, both with Virtualbox 5.0 and 5.1. I have an Intel i7, with 8 cores, but VB recognizes only 4.

I've got 8 directories in /sys/devices/system/cpu/cpu*/, but their core_id are two by two the same (that is, 0 0 1 1 2 2 3 3).

[Socratis]

@Berto: just make sure you don't confuse cores with threads. What's the exact model of your CPU? For instance on my system I have an ​Intel Core i7-2820QM, with 4 cores and 8 threads.