Svn lock takes too much time

we are using the svn source control for UE 4 project.
It’s built from source, cloned from Github.
What’s bothering us is, the “locking resource” process in Editor is very slow, it may takes 1 min or more.
Our svn depot includes the Engine source.
Any idea how to improve it?


After all, I found It’s caused by our depot includs the engine source
Currently what I do is, modifying the source of the engine

make this function only return the project folder. (The default return would return the top of the depot)