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VBox 3.0.2 noticably slower on Linux hosts

Posted: 24. Jul 2009, 02:19
by chronoboy
I have a Toshiba laptop, 1.5GHz, 1 GB of RAM.

On the laptop, I have a dual-boot setup, Windows 7 RC, and Debian Lenny. I have VirtualBox 3.0.2 running with the exact same guest configuration in both host OSes. I also did two seperate installations of Windows XP with slipstreamed SP2 in both as well.

The set-up, phase 1,2, and 3 were noticeably faster running under the Windows 7 host, at least 2.5x-3x faster. Strangely enough, less applications are running on the Linux host, and even more RAM is available under the Linux host. Also no GLX Desktop effects are enabled either.

Furthermore, on my workstation, a similar host specs, 1/3 less RAM is about the only difference, is still running VBox 2.2.4 and runs more smoothly.

This is very disappointing that the Linux version is degrading is performance, as headless mode on a Linux host works rather nicely.

Does anybody else notice these performance differences with the Linux version as well?

Re: VBox 3.0.2 noticably slower on Linux hosts

Posted: 24. Jul 2009, 09:37
by fixedwheel
On the laptop, I have a dual-boot setup, Windows 7 RC, and Debian Lenny.
...
This is very disappointing that the Linux version is degrading is performance,
whats your hdd partition layout? - the (real) inner cylinders of a hdd are about half as fast (or even worse) than the outer ones, usual logical mappings AFAIK start from the outer to the inner so the first partition is fastest

OTOH 1GB host memory is somewhat low, if your host starts swapping performance is lost at all

Re: VBox 3.0.2 noticably slower on Linux hosts

Posted: 24. Jul 2009, 19:56
by chronoboy
fixedwheel wrote:whats your hdd partition layout? - the (real) inner cylinders of a hdd are about half as fast (or even worse) than the outer ones, usual logical mappings AFAIK start from the outer to the inner so the first partition is fastest
This could be the issue, on my laptop, Windows 7 RC takes the first 20GB of space, Debian Etch begins after it. There is still a chunk of 20GB unallocated space at the end of the disk. I just thought of something else which is different in the host set-up, my Debian Lenny is using a crypto-root partition as well as LVM. Whereas Windows 7 RC is merely on a single NTFS partition, no encryption or special logical volume manager.
OTOH 1GB host memory is somewhat low, if your host starts swapping performance is lost at all
This wouldn't cause any issues on my Linux host, as there is more RAM available during operation. My guest is only using 256MB of RAM on both host configurations.

I will try creating a partition at the end of the disk with no LVM or encryption and place a VirtualBox VM on this partition and see if the performace increases. I believe that both cryptoroot and LVM are taking a lot of CPU resources on the host during normal guest disk operations.

However, my workstation is configurated with full disk encryption, no partition records(MBR) whatsoever, however my workstation does not use LVM, which may be the leading cause for the performance. I will do further tests and see what host configuration is causing the performance issues, I would hate to rid my laptop of disk encryption for the sake of virtualization performace.

Re: VBox 3.0.2 noticably slower on Linux hosts

Posted: 24. Jul 2009, 22:08
by vbox4me2
chronoboy wrote:I would hate to rid my laptop of disk encryption for the sake of virtualization performace.
Fyi. I run my work laptop also with full encryption(truecrypt) and vbox does not suffer from it.

Re: VBox 3.0.2 noticably slower on Linux hosts

Posted: 25. Jul 2009, 03:34
by Perryg
Increase to at least 2 Gig of RAM.

You need to remember that you are running (2) OSs and the overhead of the hypervisor too.
I have a PC with 1 Gig to test on and it works as you have stated your does. Drop in another gig and it was smooth sailing all the way.