[vfio-users] VM Randomly Becomes Choppy

[Okky Hendriansyah]

On February 28, 2016 at 02:00:54, ben j (btpprograms at gmail.com(mailto:btpprograms at gmail.com)) wrote:
> 
> 
> I've narrowed it down to a cpu issue, I was giving 6 cores (I only have 6) to the VM and from looking at htop it seems to start lagging from major cpu spikes. For a moment Skype spikes to 250% cpu usage when it launches which would explain why it triggered the issue. Is there a steadfast rule for cpu allocation to gaming VM's? So far 6 has been unstable, 3 has always been choppy on boot, and 4 seems fairly stable but has still occasionally gotten choppy. I'm currently testing 5 but I expect it will be worse than 4. I'm also only currently running at 3.3GHz and could easily overclock to ~3.9 if that would make a big difference. I find it difficult to believe that it's not just an optimization issue though since I've never had any issues with this cpu before.
> 
> 



Hi Ben, 

My first thought is, have you tried enabling MSI on the guest? [1] 

What kernel is the host running? Although kernel 4.4.x should fix the utterly slow boot, my guest still suffer from it when I set the guest memory > 8 GB. Which when I set the host kernel back to 4.1.x, I never encountered this issue. 

Another issue that I noticed with kernel 4.4.x, is that the CPU usage when playing any sorts of audio, be it from games or even iTunes loads a very high CPU usage (around 70%), whilst quite low at kernel 4.1.x (around 30%). 

So if your kernel is at 4.4.x now, can you try using 4.1.x? 

[1] http://vfio.blogspot.com/2014/09/vfio-interrupts-and-how-to-coax-windows.html 

Best regards, 
Okky Hendriansyah
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/vfio-users/attachments/20160228/769f8b0d/attachment.htm>