Like the resource control, the resource cap can be defined by using attributes of project entries in the project database. However, while resource controls are synchronously enforced by the kernel, resource caps are asynchronously enforced at the user level by the resource capping daemon. With asynchronous enforcement, a small delay occurs as a result of the sampling interval used by the daemon.
For information about rcapd, see the rcapd(1M) man page. For information about projects and the project database, see Chapter 2, Projects and Tasks (Overview) and the project(4) man page. For information about resource controls, see Chapter 6, Resource Controls (Overview).