Why does Octanebench V2020.1 Benchmark Linux version use 100% CPU?

It is said in this article that Octanebench is a GPU rendering benchmark, so it should not use too much CPU. It is the case on Windows. But when I run it on Linux, not only GPU is nearly 100% used, but CPU usage is also 100%. I don't understand this observation. Can you explain?

PS, The Linux version is running in WSL2 with Ubuntu 20.04.

I am not a Linux expert unfortunately but it might just not be optimized for Linux as well as it is for Windows. After all Octane's userbase is probably 90% Windows Users.