#4166 closed defect (worksforme)
Windows Guest performance worse with VT-x/AMD-V enabled
| Reported by: | Richard | Owned by: | |
|---|---|---|---|
| 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 (3)
Change History (16)
comment:1 by , 15 years ago
| Resolution: | → worksforme |
|---|---|
| Status: | new → closed |
comment:3 by , 15 years ago
| Resolution: | worksforme |
|---|---|
| Status: | closed → reopened |
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 by , 15 years ago
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:7 by , 15 years ago
I'm having the same issue. Attached are my log files.
Thanks for the great product
comment:8 by , 15 years ago
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.
by , 15 years ago
| Attachment: | SisDev2-2009-07-31-21-06-48_vt_x_on.log added |
|---|
vt-x on, 2cpu attached to vm, slower performance
by , 15 years ago
| Attachment: | SisDev2-2009-07-31-21-14-52_vt_x_off(faster).log added |
|---|
vt-x off, 1cpu, much better performance
follow-up: 10 comment:9 by , 15 years ago
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:11 by , 15 years ago
| priority: | critical → 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 by , 15 years ago
| Resolution: | → worksforme |
|---|---|
| Status: | reopened → closed |
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 by , 15 years ago
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.
Be more specific.