Rate computations of particular use in scheduling activities or items such as the sending of packets

Rate computations are performed such as for use in scheduling activities, such as, but not limited to packets, processes, traffic flow, etc. One implementation identifies an approximated inverse rate, a fix-up adjustment value, and a quantum. An activity measurement value is maintained based on a measure of activity, and a rate control value is maintained based on the measure of activity and the approximated inverse rate. The fix-up adjustment value is applied once each quantum to the rate control value to maintain rate accuracy of the activity. In one implementation, the control value is a scheduling value used for determining when to perform a next part of the activity (e.g., send one or more packets). Scheduling rates are efficiently and compactly stored in an inverse form, which may have advantages in terms of rate granularity, accuracy, and the ability to deliver service smoothly.