High number of wakeups using virtualbox

devsk · Post by **devsk** » 15. Aug 2008, 08:28

I ran powertop to see which program was causing the most wakeups on my linux host. And what I found was that virtualbox was causing nearly 1000 wakeups per second. The host is configured with NO_HZ (tickless kernel) and HZ=300.

The gues is also a linux kernel configured with NO_HZ and HZ=100. And it shows no CPU usage. The #wakeups is about 85-90 in the guest, which is reasonable.

vmware-server and vmware-player cause about 450-500 wakeups per second on the host. Why is virtualbox causing more than 1000 wakeups per second? Is there some effort to reduce this? This is one major issue for installs done on a laptop.

PS:All the numbers I talked of are in idle state.

Post by **TerryE** » 15. Aug 2008, 11:48

If you search the wiki you will find some caveats about using tickless kernels

devsk · Post by **devsk** » 15. Aug 2008, 16:53

TerryE wrote:If you search the wiki you will find some caveats about using tickless kernels

I did compare it against a non-tickless kernel as well. And the result was pretty much the same. And, I did not get any problems in vobx with tickless kernel, in the host or in the guest. But vbox's wakeups didn't really go down with tickless.

This is something that's stopping me from installing VB on my laptop.

Post by **TerryE** » 15. Aug 2008, 17:41

devsk, can you provide some basic info here as per the Forum Posting Guide.

What is your host config: H/W config, Linux distribution, version, kernel version (uname -r), key scheduling parameters.
Ditto the guest
What version of VB is installed (version and edition: PUEL/OSE) on host
Ditto GA on guest
What key virtualisation parameters are specified:Memory, ACPI, IO APIC, VT-x, PAE, devices enabled?
You say you have tried some variations so which one?

We would need to know this sort of info to comment in detail. You would need to know this info to diagnose your problem, but you are sitting in front of your machine. As to us, we're not psychic, so please provide it up front and don't expect us to guess. No Twenty Questions, eh? When you've done so, I will ask one of the Sun guys to comment.

devsk · Post by **devsk** » 16. Aug 2008, 04:08

Host:
AMD 3800 X2, nForce4, 2GB RAM
gentoo x64_64, 2.6.25.7, NOHZ, HZ=300, SMP, deadline IO scheduler, voluntary preemption.
virtualbox-bin-1.6.4 (PUEL)

Guest:
gentoo x86, 2.6.24, NOHZ, HZ=100, with boot params="noapic nolapic nosmp", voluntary preemption.
guest additions 1.6.4
Memory=512MB, VRAM=32MB.
No VT-x. No PAE. IO APIC disabled.

Let me know if you need more info.

devsk · Post by **devsk** » 28. Jan 2009, 07:06

Is there any effort towards reducing these? This drains my laptop at a much faster (2x) rate than vmware. vmware player has reduced the wakeups to under 400 whereas I continue to get more than 1000 wakeups from idle using virtualbox.