Our application runs on the client and server of Minecraft.
It's quite a performance critical on the server as we have a lot of entities and at the same time, a lot of players and all of that currently runs on one core (The Minecraft world ticks entities only on one core).
Performance tuning could be definitely something we could need.
We also wanted to set up a nice system which logs us the performance of the different systems we have, so we discover our weak points more easily, but as I wrote before, we're missing manpower for those tasks.