Gitlab Performance Tuning

We are running Gitlab EE onsite and are having some performance issues. Load times are slow, usually on the order of a few seconds when loading a data heavy page (i.e. the pipelines page for our main repository). This problem is markedly worse in the morning, where even simple pages can take over 10s to load.

With the addition of Prometheus monitoring, it seems like a good time to use this data to try and optimize Gitlab. What metrics should I be looking at to try and decipher what is causing slowdowns, and are there any general tips tuning Gitlab’s performance?