[seL4] I Have some questions about the domain mechanism in the seL4

For some reason, i m learning the scheduling module in seL4. I have read the manual and the source code, and i have already read the answer in the link https://lists.sel4.systems/hyperkitty/list/devel@sel4.systems/thread/VYRTG3I... But i still do not know the purpose of adding the domain mechanism in seL4, Can anyone explain what kind of requirement led to the design of the domain mechanism? Please explain it more specifically, and it would be best if there were relevant documents and papers on the domain mechanism.