Re: [Qemu-discuss] High host CPU load and slow Windows 10 vm after upgrade to 1803

[utdilya]

Hello.
I have this problem too, on Centos7 with qemu.kvm on the 4 different
machines.
Tell me please, do you have resolved this problem?
My windows 10 after upgrades to 1803 has too much interrupts
more than 2000. I think it is RTC (Real Timer Clock) interrupts.
Because of this VirtualMachine has 10-20% CPU load in idle state.
See attachment:

Thank you.


On 10.06.2018 22:38, Giovanni Panozzo wrote:
> Hi to all, I'm new in this ML.
>
> After upgrading some VM from Windows 10 1709 to Windows 10 1803, the
> VMs runs slower. And when VM is almost idle, host CPU load is quite high.
>
> It happens on 4 different hardware platform (AMD FX 4300 and intel
> core i3/i5), with Arch and ubuntu 16.04/18.04 with libvirt. I already
> asked help on askubuntu.com and opened a bug to quemu with non answers.
>
> So I continued my investigation, but it's very difficult for me to
> investigate, having limited time and knowledge on Kvm/Qemu.
>
> perf kvm --host stat live reports:
>
> Analyze events for all VMs, all VCPUs:
>
>              VM-EXIT    Samples  Samples%     Time% Min Time    Max
> Time         Avg time
>
>       IO_INSTRUCTION      17379    54.45%    49.37% 4.73us  
> 5274.05us     40.94us ( +-   1.89% )
>             MSR_READ       5382    16.86%     1.56% 2.24us  
> 2126.01us      4.17us ( +-  12.26% )
>        EPT_VIOLATION       3183     9.97%     3.63% 2.83us  
> 8829.17us     16.44us ( +-  24.23% )
>            MSR_WRITE       2425     7.60%     0.80% 3.12us   
> 220.26us      4.77us ( +-   1.96% )
>   EXTERNAL_INTERRUPT       1464     4.59%     3.05% 1.99us  
> 7080.61us     29.98us ( +-  26.92% )
>    PENDING_INTERRUPT        999     3.13%     0.29% 2.87us     
> 7.12us      4.13us ( +-   0.31% )
>                  HLT        662     2.07%    41.16% 2.75us  
> 7956.90us    895.99us ( +-   2.27% )
>  TPR_BELOW_THRESHOLD        220     0.69%     0.08% 3.61us    
> 94.16us      5.55us ( +-   7.33% )
>               VMCALL        171     0.54%     0.05% 2.30us    
> 58.09us      4.20us ( +-   8.11% )
>                CPUID         24     0.08%     0.00% 2.05us     
> 4.12us      2.84us ( +-   4.05% )
>        EPT_MISCONFIG          7     0.02%     0.01% 23.05us    
> 32.87us     25.97us ( +-   4.98% )
>
> Total Samples:31916, Total events handled time:1441189.06us.
>
> And perf kvm --host stat live --event=ioport
>
>
> Analyze events for all VMs, all VCPUs:
>
>       IO Port Access    Samples  Samples%     Time% Min Time    Max
> Time         Avg time
>
>            0x70:POUT      11138    49.69%    85.13% 8.60us   
> 392.56us     30.34us ( +-   0.99% )
>             0x71:PIN      11138    49.69%    14.63% 3.80us    
> 58.95us      5.21us ( +-   0.16% )
>          0xc010:POUT        110     0.49%     0.12% 2.65us    
> 11.67us      4.15us ( +-   4.13% )
>           0x1f0:POUT          6     0.03%     0.06% 13.81us    
> 82.45us     37.23us ( +-  34.19% )
>            0x1f7:PIN          4     0.02%     0.01% 4.99us     
> 6.12us      5.62us ( +-   4.36% )
> [...]
>
> On another virtualization host, I noticed also traffic on io port 0x0608:
>
> Analyze events for all VMs, all VCPUs:
>
>       IO Port Access    Samples  Samples%     Time% Min Time    Max
> Time         Avg time
>
>            0x70:POUT       4220    40.00%    90.93% 3.42us  
> 2023.80us     12.61us ( +-   3.97% )
>             0x71:PIN       4220    40.00%     5.70% 0.53us     
> 9.23us      0.79us ( +-   0.65% )
>            0x608:PIN       2074    19.66%     3.15% 0.55us    
> 10.62us      0.89us ( +-   0.95% )
>           0x1f0:POUT          6     0.06%     0.06% 4.64us     
> 8.51us      5.54us ( +-  11.23% )
>          0xc070:POUT          5     0.05%     0.05% 4.06us     
> 7.09us      5.49us ( +-  10.68% )
>            0x1f7:PIN          4     0.04%     0.00% 0.65us     
> 0.70us      0.68us ( +-   2.10% )
>          0xc010:POUT          3     0.03%     0.04% 6.26us     
> 9.15us      7.40us ( +-  11.99% )
>
> when running older Windows 10 1709 VM, 0x70 and 0x71 IO port Samples
> value are around 120-130 with spikes to 500, on Windows 10 1803, as
> you can see, 4000 to 11000 samples.
>
> Thank you in advance for any help.
>
> Giovanni
>
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win10_1803_interrupts.png
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