The present invention provides improved work schedulers for computer systems and communication processors. A preferred embodiment of the present invention includes systems with buffer memory for storing one or more communication packets or work requests arranged on a plurality of scheduling queues and information for controlling the scheduling of the queues, with output processors for outputting packets from the buffer memory; and with control processors for performing the scheduling methods of this invention. The scheduling methods repetitively initialize each queue's service credits, repetitively process each queue in a round-robin order by granting each queue with remaining service credits no more than one quantum of service and updating that queue's service credits to reflect the service actually used and the service available for use but not actually used.