Dom0 CPU usage goes high if DomU is under heavy loading

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Dom0 CPU usage goes high if DomU is under heavy loading

Tom Ting[丁郁庭]

Hi All

 

I’ve encounter following issue and need your advice.

 

Platform setting :

ARM64, 4 physical CPU, XEN-4.6

Dom0 :

- Network backend

- Running high wifi throughput (extremely high interrupt rate)

DomU :

- Media playback, 3D Graphic

- Video/GPU is using passthrough driver

- hooked to network via VIF

 

If Dom0 is running high network throughput and DomU is under idle state, Dom0 consumes about 140~150% observed from xentop.

Now we let DomU do some heavy workloads(ex: high-resolution-playback/3D graphic/consumes about 160%), Dom0 CPU will be affected and goes up to 190%.

I’ve tried to adjust parameters on credit-scheduler but improvement is limited.

Really appreciate for your adjustment or advice.

 

 

Thanks

Tom


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Re: Dom0 CPU usage goes high if DomU is under heavy loading

Simon Hobson-2
Tom Ting[丁郁庭] <[hidden email]> wrote:

> I’ve encounter following issue and need your advice.
>  
> Platform setting :
> ARM64, 4 physical CPU, XEN-4.6
> Dom0 :
> - Network backend
> - Running high wifi throughput (extremely high interrupt rate)
> DomU :
> - Media playback, 3D Graphic
> - Video/GPU is using passthrough driver
> - hooked to network via VIF
>  
> If Dom0 is running high network throughput and DomU is under idle state, Dom0 consumes about 140~150% observed from xentop.
> Now we let DomU do some heavy workloads(ex: high-resolution-playback/3D graphic/consumes about 160%), Dom0 CPU will be affected and goes up to 190%.
> I’ve tried to adjust parameters on credit-scheduler but improvement is limited.
> Really appreciate for your adjustment or advice.

AIUI, all networking is done, by default, by one thread in Dom0. I could imagine a high network load (in terms of packets processed rather than bytes passed) could well result in a significant Dom0 load. I do know that this has been fingered in the past as a source of network bottleneck.


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