High CPU Usage

[mmolaie]

hello
i have install kasmvnc on docker ubuntu 20.04
hight CPU Usage on Xvnc when connect to it. Over 200%
what should i do?

[mmcclaskey]

Sorry for the delayed response. Are you still experiencing this issue. If so, can you provide the output of top so I can see what other processes are going on.

[ich777]

@mmcclaskey hi, thank you for the Debian Bookworm build. I'm running into some issues where I get really high CPU usage when something is moving on the screen (Intel i5-10600 60-70% utilization) is this expected? Most certainly I'm missing something.
I passed through /dev/dri to the container and I also can see that my iGPU is used from Xvnc but the CPU usage stays really high.

Don't know if I should post in #163 or here but I think this issue is more appropriate.

If you need anything please let me know, attached also a few pictures:

[mmcclaskey]

It looks like there are a lot of Xvnc processes running, can you explain what is going on there?

What is your desktop environment? Can you try disabling compositing in your desktop environment to see if the CPU utilization drops?

[ich777]

I really don't know, I just start the kasmvncserver and after that xfce4-session (I use XFCE4) and then this happens.

Disabling compositing also doesn't help, it looks pretty much the same.

[thelamer]

@ich777 no this is not normal, please post the exact methodology you used to start kasmvncserver and the accompanying logs. (pastebin)
There should only ever be one Xvnc pid in your tree.

[ich777]

@thelamer sure thing, I uploaded the logs here: kasmvnc.log

I just do that:

kasmvncserver :0 -noxstartup -hw3d -disableBasicAuth
xfce4-session --display=:0

[ich777]

Still not solved but I give up on KasmVNC.

[thelamer]

Despite support for GPUs for the actual desktop session all of our encoding methods are done in pure CPU. I think some of the confusion in this thread is us looking at the htop output and concluding many Xvnc instances are running at once but that is just how htop displays threaded applications.
With a video playing back or high movement KasmVNC will use all the CPU it can get it's hands on to attempt to deliver rects at 60fps.

[mmcclaskey]

For others that run into this issue, KasmVNC by default will automatically create N number of threads based on how many cores your system has. It looks like for @ich777 system KasmVNC was creating a lot of threads for encoding. You can override the encoding.rect_encoding_mode.rectangle_compress_threads setting, if for some reason Kasm is being overly greedy. Perhaps you are running it on a system with a lot of cores and hyperthreads, we don't really have a lot of information to go on. Since the submitter gave up on kasmvnc, I will close the issue. If others run into this, try adjusting this setting and provide us more details on your system and what setting worked for you.

https://www.kasmweb.com/kasmvnc/docs/latest/configuration.html#encoding