Very slow guest performance on VB 4.1.8-75467

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-Manuel-
Posts: 3
Joined: 24. Feb 2012, 23:02

Very slow guest performance on VB 4.1.8-75467

Post by -Manuel- »

I've installed VB 4.1.8-75467 on a Dell Studio (Intel i5, 8GB RAM) today. If I start a RHEL 6 VM it starts very very slowly. The VM is absolutely unusable. Before I had VB 3 installed and the performance on all VMs was excellent. Have you got any idea what could be wrong with VB 4 and my Dell Notebook?

Thank you very much for your help.

Manuel
Perryg
Site Moderator
Posts: 34369
Joined: 6. Sep 2008, 22:55
Primary OS: Linux other
VBox Version: OSE self-compiled
Guest OSses: *NIX

Re: Very slow guest performance on VB 4.1.8-75467

Post by Perryg »

You would need to provide some hard information for us to tell. Post the guests log file (as an attachment).
-Manuel-
Posts: 3
Joined: 24. Feb 2012, 23:02

Re: Very slow guest performance on VB 4.1.8-75467

Post by -Manuel- »

Hello Perryg
Sorry about that. I attached the log file of a rhel 6 vm which is very slow (about 7 Minutes!!) to start. Before with VB 3 it took only about 30 seconds.

Thank you very much for your help.

Manuel
Attachments
VBox.log
VBox.log of RHEL 6.2 VM
(78.25 KiB) Downloaded 73 times
mpack
Site Moderator
Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Very slow guest performance on VB 4.1.8-75467

Post by mpack »

There are a lot of lines in the log beginning "PIT". I assume this is "Programmable Interval Timer". On my VMs (which run very sweetly) this gets set 3 or 4 times, usually with an interrupt frequency of 18.2Hz, the fastest being 100Hz. Your log shows a large number of consecutive events, with some crazy frequencies: one line has 85000Hz!

I don't know what is causing this, presumably some crappy bit of software installed in the guest is banging the hell out of the hardware timers. Unless that's the GAs (which might be embarrassing), then it looks like it isn't a VBox problem. Even running native this would be an excessive CPU overhead.
-Manuel-
Posts: 3
Joined: 24. Feb 2012, 23:02

Re: Very slow guest performance on VB 4.1.8-75467

Post by -Manuel- »

Hello mpack
I've got the solution! I created a complete new VM for rhel6 and made a base installation. The new vm was running very well so I compared the settings from my very slow vm created along time ago with VB 3 and noticed that on the newly created vm under VB 4 "Enable IO APIC" (System --> Motherboard --> Extended Features) was selected. I selected it too and surprise surprise, the vm runs as expected!

Thank you very much for your help! I'm very happy now!

Manuel
Perryg
Site Moderator
Posts: 34369
Joined: 6. Sep 2008, 22:55
Primary OS: Linux other
VBox Version: OSE self-compiled
Guest OSses: *NIX

Re: Very slow guest performance on VB 4.1.8-75467

Post by Perryg »

Normally I see this with RT kernels in a virtual machine.
You can set the timer frequency to 100Hz (optimal for virtual Linux machines) just by adding divider=10 as the kernel option and fix this. I am not sure how IO APIC would affect this and allow it to work, but if you still have an issue try the divider.
gearge
Posts: 5
Joined: 24. Apr 2011, 20:22
Primary OS: Ubuntu 12.04
VBox Version: PUEL
Guest OSses: debian, rhel, FreeBSD

Re: Very slow guest performance on VB 4.1.8-75467

Post by gearge »

I can confirm, that selecting the "Enable IO APIC" (System --> Motherboard --> Extended Features: "Enable IO APIC") fixed the major performance issue associated with using a Red Hat Enterprise Linux 6.x x86_64 guest in VirtualBox 4.x.
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