Host CPU is 100% when os/2 guest has a SMP kernel

[James Moe]

When a guest os/2 system is using a SMP (multiprocessing) kernel, the host CPU usage goes to 100% for each allowed CPU.

The host is a quad AMD athlon CPU (630-x4), the guest is allowed 2 CPUs. When the VM is started, two of the host CPUs' usage goes to 100%. Inside the VM the CPU usage shows a typical 2 - 4%.

This is not a problem for the uniprocessor kernel.

openSUSE v12.3 linux 3.7.10-1.4-desktop x86_64

[James Moe]

Log file of os/2 guest with 100% host cpu usage

[Yoda]

This is a known design for the SMP kernel. It has the CPU HLT instruction disabled, so it will never go to sleep; which causes the high CPU use on host.

Install the latest ACPI driver, which has a workaround for this problem.

[James Moe]

I tried ACPI v3.22.02. It made no difference, with or without the /NOHLT option.

[Yoda]

That sounds very weird. Currently I have 2 eCS guests running on my nix-server. Both use 2 Vcpus

Host shows CPU usage of less than 10% on all 4 cores.

I have ACPI 3.22.03 on both.

You should not use any /parameters with Vbox guests

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.