Possibly nobody noticed it: as software engineer a have a bias into computing efficiency and resources availability. I first noticed the following:
- Start Task Manager in Windows > tab ‘Performance’
- Start a SimScale meshing or simulation process with your browser.
- Observe CPU Usage, when moving back cursor to browser tab with SimScale running meshing (move then to different tab and back to SimScale tab). CPU usages is up, when you are in SimScale running meshing.
- Go to Task Manager > Processes tab. Click on CPU column header in order to sort CPU time (having active processes on the top). Move back to browser SimScale tab, observe Task Manager processes list.
Bottom line is: when you focus (move cursor) on SimScale simulation (meshing) window in your browser, CPU usage goes up by by at least 5%, despite the fact that no rendering is active (your hands on the desk).
You will find out, that meshing announces in the log, that it is done, but core hours are still incremented. CPU is consumed (if focus is on that window) till twice the time first meshing part (‘mesh ended’) is done. Example: meshing log said ‘done’ in 5 core hours, SimScale will tell you that meshing is done in 10 core hours. CPU activity starts immediately after notice from SimScale that meshing is ready.
In reality it is more complex. I use Chrome and have Nvida graphic board. Chrome knows how to communicate with my Nvidia by separate process. When running meshing with focus on SimScale simulation window, Nvidia is also used, at about 5-6% of capacity. I used different tools to look into that bizarre behaviour, and convince myself about ‘impossible’, but presented here only basic checks, everybody can reproduce.
- Lousy programming, forgotten threads, easter eggs, whatever.
- OpenFoam programs ‘rent’ remote computers, when they are kind enough to keep focus on simulation window.
- Crypto mining is running in the background, gently picking resources when using SimScale in meshing or simulation mode.
Here is the screen shot of Process Explorer, while I’m in a simulation. You can see two chrome processes at near 5%.