VirtualBox

Ticket #4166 (closed defect: worksforme)

Opened 5 years ago

Last modified 5 years ago

Windows Guest performance worse with VT-x/AMD-V enabled

Reported by: cornbread Owned by:
Priority: major Component: other
Version: VirtualBox 2.2.4 Keywords:
Cc: Guest type: Windows
Host type: Linux

Description

This turns out to be true on every host with a windows guest I've tried it on now (Total 6)

Speed improvement on anything that requires processing power. Using amd and intel hosts.

Attachments

Logs.zip Download (22.3 KB) - added by homerhomer 5 years ago.
my log files
SisDev2-2009-07-31-21-06-48_vt_x_on.log Download (64.2 KB) - added by dinismiguel 5 years ago.
vt-x on, 2cpu attached to vm, slower performance
SisDev2-2009-07-31-21-14-52_vt_x_off(faster).log Download (61.3 KB) - added by dinismiguel 5 years ago.
vt-x off, 1cpu, much better performance

Change History

comment:1 Changed 5 years ago by sandervl73

  • Status changed from new to closed
  • Resolution set to worksforme

Be more specific.

comment:2 Changed 5 years ago by frank

That is, which benchmark did you use?

comment:3 Changed 5 years ago by cornbread

  • Status changed from closed to reopened
  • Resolution worksforme deleted

Plain old trial and error.

When it takes 30 + minutes to run a report then you go ant turn off VT-x/AMD-V and then it only takes 10. You turn it back on and it takes 30+ again. That is a pretty good tell tale.

Here is a forum post of a couple others that have figured this out.

 http://forums.virtualbox.org/viewtopic.php?f=2&t=13720

I have also noticed this with photo rendering on the two computers running lightroom. Lightroom is unusable due to extremely long photo rendering when VT-x/AMD-V is running turn it off and it is still slow but bearable.

comment:4 Changed 5 years ago by sandervl73

It would save us a lot of time if you include more information in the future. That forum topic mentions it happened since 2.1. For some/most it was fixed in 2.1.4.

Attach your VBox.log as well please. Both Intel and AMD hosts.

comment:5 Changed 5 years ago by cornbread

do you want the log with VT-x/AMD-V enabled on those hosts?

comment:6 Changed 5 years ago by sandervl73

Yes, thanks.

Changed 5 years ago by homerhomer

my log files

comment:7 Changed 5 years ago by homerhomer

I'm having the same issue. Attached are my log files.

Thanks for the great product

comment:8 Changed 5 years ago by dinismiguel

I'm using vb 3.0.2r49928 with a centrino duo t2400 and with VT-x enabled the performance is much worse. I'll attach both logs with and without vt-x enabled.

Changed 5 years ago by dinismiguel

vt-x on, 2cpu attached to vm, slower performance

Changed 5 years ago by dinismiguel

vt-x off, 1cpu, much better performance

comment:9 follow-up: ↓ 10 Changed 5 years ago by dinismiguel

I forget to say, my tests was plain old trial and error too, things like boot and time, applications start up time, some code compilation, the system responsiveness, it was easy to distinguish is not a small difference it's nearly 2x speed.

comment:10 in reply to: ↑ 9 Changed 5 years ago by dinismiguel

The problem persists in VirtualBox 3.0.4 r50677

comment:11 Changed 5 years ago by sandervl73

  • Priority changed from critical to major

dinismiguel: your problem is IO-APIC related, because your CPU doesn't support the VMX_VMCS_CTRL_PROC_EXEC2_VIRT_APIC feature. That kills performance. There's another defect for this (search for IO-APIC) and report there please.

comment:12 Changed 5 years ago by sandervl73

  • Status changed from reopened to closed
  • Resolution set to worksforme

Same for homerhomer (AMD & IO-APIC).

I'll close this defect as the original reporter didn't provide logs. Only reopen when providing a VBox.log and after checking IO-APIC is turned off.

comment:13 Changed 5 years ago by dinismiguel

sandervl73: As you said, i turned off the IO-APIC feature in virtualBox machine settings. Have to replace the windows XP(guest) kernel to an non APIC one. VirtualBox don't let me to use more than one core without this feature but now the vt-x seems to be working fine because the seed increased a lot. it would be great if both cores could be used without IO-APIC. But now the performance is very acceptable. I think, in the future versions, the lack of VMX_VMCS_CTRL_PROC_EXEC2_VIRT_APIC support should be detected and the GUI behavior should express that to avoid this problem. Many thanks, i consider this subject resolved.

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