High CPU usage after RDP disconnection

[gabrieletassoni]

HI,
I'm running, since some days, a proxmox Virtual Environment 6.3-2 with one Windows 10 Professional (version 20H2) guest.
I installed virtio drivers 0.1.190 and virtio guest tools 0.1.190.
Had to disable Ballooning from the guest Memory configuration since it was giving very high CPU usage and at least twice a day it was crashing the windows guest.

I'm using Remmina as RDP client from my Ubuntu.

The Host hardware is:

$ lscpu
Architecture:                    x86_64
CPU op-mode(s):                  32-bit, 64-bit
Byte Order:                      Little Endian
Address sizes:                   36 bits physical, 48 bits virtual
CPU(s):                          4
On-line CPU(s) list:             0-3
Thread(s) per core:              1
Core(s) per socket:              4
Socket(s):                       1
NUMA node(s):                    1
Vendor ID:                       GenuineIntel
CPU family:                      6
Model:                           23
Model name:                      Intel(R) Xeon(R) CPU           X3370  @ 3.00GHz
Stepping:                        10
CPU MHz:                         2073.761
CPU max MHz:                     3000,0000
CPU min MHz:                     2000,0000
BogoMIPS:                        6000.33
Virtualization:                  VT-x
L1d cache:                       128 KiB
L1i cache:                       128 KiB
L2 cache:                        12 MiB
NUMA node0 CPU(s):               0-3
Vulnerability Itlb multihit:     KVM: Mitigation: Split huge pages
Vulnerability L1tf:              Mitigation; PTE Inversion; VMX EPT disabled
Vulnerability Mds:               Vulnerable: Clear CPU buffers attempted, no mic
                                 rocode; SMT disabled
Vulnerability Meltdown:          Mitigation; PTI
Vulnerability Spec store bypass: Vulnerable
Vulnerability Spectre v1:        Mitigation; usercopy/swapgs barriers and __user
                                  pointer sanitization
Vulnerability Spectre v2:        Mitigation; Full generic retpoline, STIBP disab
                                 led, RSB filling
Vulnerability Srbds:             Not affected
Vulnerability Tsx async abort:   Not affected
Flags:                           fpu vme de pse tsc msr pae mce cx8 apic sep mtr
                                 r pge mca cmov pat pse36 clflush dts acpi mmx f
                                 xsr sse sse2 ht tm pbe syscall nx lm constant_t
                                 sc arch_perfmon pebs bts rep_good nopl cpuid ap
                                 erfmperf pni dtes64 monitor ds_cpl vmx smx est
                                 tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm p
                                 ti tpr_shadow vnmi flexpriority dtherm

With 8 GB RAM, 6G are assigned to the guest and 1 socket with 2 cores assigned to the Guest.

After removing ballooning it started behaving right, quite low on CPU (around 10%) and stable for some days, with the only problem, it seems, to go high on CPU if disconnecting from a RDP session. After rebooting the guest, if no RDP connection is attempted, the problem doesn't appear (at least for a couple of days, then I got into RDP and the problem resurfaced), now I'm stuck at having an RDP session always on until next reboot (maybe this night), to allow people continue their work (the Windows 10 Pro acts as a shared folders server in this small network).
What can I do to debug and overcome the problem? I found other posts in this forum speaking about RDP disconnection and high CPU usage, but where something was suggested as a fix, I tried it but still have the problem.

Thank you very much for any help.
Gabriele

 

[gabrieletassoni]

I'm also noticing something strange, but maybe it's just uncorrelated and I'm mis-correlating it: if I put Remmina's RDP client in the background, below another window (I noticed now, using this browser above the RDP client window, but not fullscreen so to be able to see the Window's task manager below), after several minutes I don't interact with the remote desktop, the CPU on the Windows Guest starts to go up again, not as much as with RDP session disconnected but high anyway. The windows process that goes up is System and as soon as I focus again the RDP Client window and click on the windows desktop, System suddenly falls down to about 3% CPU.