This Moodle performance overview proposal page is created in response to Moodle issue [https://tracker.moodle.org/browse/MDL-35716 MDL-35716]
The general problem from the issue seems to be the related to users not having insight into what configuration settings they have turned on or off that may affect Moodle performance.
My proposed solution is to create a "Performance overview" page, similar to the existing "Security overview" page that lists performance-related configuration settings for a Moodle site, along with a suggestion to what the setting should be set, and allow the user to modify individual settings by visiting the setting's link.
I've added a link to a UI screenshot of what this can look like. It lists just some of the possible configuration settings that relate to performance. A new "Performance overview" page is added in the settings block: Site Administration > Reports > Performance overview
One issue with creating this performance overview page is with how performance improvement suggestions are subjective. Changing the value of one particular setting may impact Moodle performance differently depending in what environment it's in. Therefore, these would be suggestions that will "generally" improve Moodle performance.
Currently this design requires no database modifications to Moodle except maybe an addition to capabilities/permissions defined in access.php.