VT-x causes massive DPC latency
|Reported by:||maqr||Owned by:|
|Guest type:||Linux||Host type:||Windows|
Description (last modified by )
I am running Windows 7 x64 on a q6600 with virtualization enabled in the bios. Whenever my guest (x64 or x86) is under any kind of load (even just booting the Ubuntu installer), I get big DPC latency spikes. This is obviously a problem because it causes choppy audio, video, and generally degrades performance. Once inside the guest OS, this is can be easily reproduced with a simple bash script:
while true; do ""; done
I have reproduced this on an i7 920 with the same problem.
Attached is a dpclat screenshot and a dump from xperf. If the ETL would be beneficial in debugging, I could produce one.
The "fix" for me was to install a 32-bit guest and disable VT-x in the vbox options.