Performance problems in 2.9

I've been running gmoccapy on lcnc 2.8 for a couple years on my mill.  I recently upgraded to Debian Bullseye and building 2.9 from source so I can use the switchkins for an XYZAC config. 

Now when I start up, the performance is very laggy.  The UI takes several minutes to appear and is unusable.  Button clicks take 30 seconds or more to register.

I switched the config to use Axis and it works normally.  This isn't a particularly powerful PC but it has been fine until now.

Also, I'm seeing the same thing if I try a gmoccapy sim configuration. 

First, is there any known problems I should be aware of? 
Second, how can I debug this?

Nope. No user tabs.

Not really any new info. I left it running overnight to see what would happen. Sitting idle, the python process is pulling 99% of cpu. Not consuming much memory.

/usr/bin/python3.9 /home/brad/linuxcnc/bin/gmoccapy -ini /home/brad/linuxcnc/configs/millstone/Supermax.ini

I rebuilt the machine from scratch.  This time I used Debian 10 (buster).  XFCE4  I installed packages
linuxcnc-uspace_2.9.0~pre0.4421.ge060ed441_i386.deb
linuxcnc-uspace-dev_2.9.0~pre0.4421.ge060ed441_i386.deb

Then trying just the gmoccapy 4 axis config (has no user tabs embedded) I get an error about missing icons in the Tango theme.Then the UI displays the borders of two windows but fails to finish painting.The CPU pegs out at 110% as reported by htop.  (4 core CPU). Attaching the report.

Am I the only one seeing this?

Update.
I still don't have a resolution to this but it's related to the PC hardware.  I pulled the drive out and stuck it in another intel box and it works great. 
Nothing special about the PC.  4-core Intel with onboard VGA.
Works great with Axis and has run gmoccapy in the past.  Now runs fine with Axis but locks up launching gmoccapy.
I'll get specs off the board next time I boot it up but maybe someone has seen this already.

No, you're not alone. I realise this is a slightly old thread but it seems a fair match - happy to create a new one if required.

I have a very nice little 'industrial' Intel NUC i5-3427U 8GB RAM (ark.intel.com/content/www/us/en/ark/prod...-up-to-2-80-ghz.html) that runs very well - except for gmoccapy which averages 44% CPU and often goes over 50%. 



In my original vanilla 2.8.4, with a MESA card, the CPU usage hovered around 40% causing the CPU to hit 90°C+ so I decided to install Debian 12 and LinuxCNC on a new hard drive (and WiFi card for reasons) in the hopes it would resolve the issue. It's worse! I'm running the gmoccapy SIM on a fresh vanilla install the CPU usage is there even when the machine is not turned on.

QtDragon XYZ Metric SIM uses about 5% CPU on the same setup.

The CPU usage I am seeing in 'top' is gmoccapy not Python as per OP.

Did you try reducing the cycle time (INI setting)?Default is 100 , try to set the value to 150 or 200

Thank you Zdeněk  - I did wonder if there was a 'frame/loop rate' (when I first wrote the Manualmatic code I hit 100% CPU!).

I've tried a number of different values but even at 500 I'm still hovering around 20% CPU with the machine not turned on and everything idle - and unsurprisingly it now feels very laggy.