Systems and methods for rate-limited weighted best effort scheduling

摘要

Systems and methods for scheduling data packets in a network processor are disclosed. Embodiments provide a network processor that comprises a best-effort scheduler with a minimal calendar structure for addressing schedule control blocks. In one embodiment, a four-entry calendar structure provides for rate-limited weighted best effort scheduling. Each of a plurality of different flows has associated schedule control blocks. Schedule control blocks are stored as linked lists in a last-in-first-out buffer. Each calendar entry is associated with a different linked list by storing in the calendar entry the address of the first-out schedule control block in the linked list. Each schedule control block has a counter and is assigned a rate limit according to the bandwidth priority of the flow to which the corresponding packet belongs. Each time a schedule control block is accessed from a last-in-first-out buffer storing the linked list, the scheduler generates a scheduling event and the counter of the schedule control block is incremented. When an incremented counter of a schedule control block equals its rate limit, the schedule control block is temporarily removed from further scheduling until a time interval concludes.