Process "warmd" keep busy mac after upgrading to macOS 10.14.4
Have a read of the following;

Provisioning OSX and disabling unnecessary services

It has instructions on how to disable warmd. I can not confirm they are still relevant at this stage as I myself am installing the latest OSX as we speak. I will provide more details after that install finishes.

TL;DR

Kill warmd: sudo launchctl kill -9 system/com.apple.warmd

Disable warmd: sudo launchctl disable system/com.apple.warmd