VirtualBox can't use all cores on Macbook Pro

[XGhosT192]

Good afternoon.

I install VirtualBox on Macbook Pro 2016 (13" retina).
CPU is 2.7 GHz Intel Core i5, 2 core / 4 logical cores.

Activity Monitor can see all (4) core

cpu activity.png (28.98 KiB) Viewed 2139 times

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bash-3.2$ sysctl -n hw.ncpu
4
bash-3.2$ sysctl -n hw.physicalcpu
2
bash-3.2$ sysctl -n hw.logicalcpu
4

But VirtualBox can not see more than 2 core!

How i can fix this?
And VirtualBox can see on my hardware all of logical cores

[socratis]

VirtualBox cares about physical processors (cores), not logical ones (threads). So, the number to look at would be:

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bash-3.2$ sysctl -n hw.physicalcpu
2

not

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bash-3.2$ sysctl -n hw.logicalcpu
4

If you want a more detailed analysis, we're going to need a complete VBox.log, from a complete VM run:

• Gathering the necessary information:
  1. Start the VM from cold-boot (not from a paused or saved state).
  2. Observe the error, i.e. check out the Activity Monitor in the host, in parallel with the Task Manager in the guest.
  3. Shutdown the VM (force close it if you have to).
• With the VM completely shut down (not paused or saved), right-click on the VM in the VirtualBox Manager and select "Show Log".
• Save only the first "VBox.log", ZIP it and attach it to your response. See the "Upload attachment" tab below the reply form.

[XGhosT192]

Thanks a lot.

I collect logs of VM (in attach).
Host OS is Mac OS High Sierra, guest os is Cent OS 7.

VirtualBox give me a warning about incorrect CPU number

CO-VBox-CPU.png (78.53 KiB) Viewed 2130 times

And tis is what i see in guest OS (4CPU) and Host OS via Activity monitor.

CentOS-4-cpu.png (45.2 KiB) Viewed 2130 times

But i think some cores in guest os are malfunction...


P.S.

VirtualBox cares about physical processors (cores), not logical ones (threads). So, the number to look at would be:

Hmm... on another platform (AMD APU) i have also 2 phisical cores and 4 logical.
But VirtualBox see all of them.

[XGhosT192]

And another strange thing is 100% disk busy on Linux under mac os

disk busy.png (28.95 KiB) Viewed 2129 times

[socratis]

00:00:02.325720 CPUM: Logical host processors: 4 present, 4 max, 4 online, online mask: 000000000000000f
00:00:02.325724 CPUM: Physical host cores: 2
00:00:02.233851 NumCPUs <integer> = 0x0000000000000004 (4)
00:00:02.326043 Full Name: "Intel(R) Core(TM) i5-5257U CPU @ 2.70GHz"

As I mentioned, you have assigned all your CPUs to the VM. The host is going to run low on resources, since VirtualBox cares about physical processors (cores), not logical ones (threads). See "CPU Cores versus threads" and "Why is it a bad idea to allocate as many VCPUs as there are physical CPUs?".

Also, take a look at Intel's specifications about your i5-5257U CPU. Click on the "?" next to the "Cores" and the "Threads"...

• A Core is a hardware term that describes the number of independent central processing units in a single computing component (die or chip).
• A Thread, or thread of execution (or logical CPU), is a software term for the basic ordered sequence of instructions that can be passed through or processed by a single CPU core.

Source: http://ark.intel.com

Hmm... on another platform (AMD APU) i have also 2 phisical cores and 4 logical. But VirtualBox see all of them.

I need to see a VBox.log from that, I can't be making assumptions, it's dangerous to assume without knowing what the heck I'm talking about...