Distributed scheduling system for transmission of real-time data via bus and loss-sensitive and non-real-time data

摘要

Data is transferred between one device and another device over the bus, or between one device and another system resource, such as a central processing unit. This data is categorized into one of several forms. Hard real-time data must be transmitted within a specified time limit or deadline, and no missed deadlines are allowed. Soft real-time data must also be transmitted before the deadline, and although it is acceptable to miss some deadlines, the fewer missed deadlines are better. Loss sensitive data does not have a deadline, but no data loss is acceptable. Non-real-time data also has no deadlines, but less time delay in transferring data is better. In accordance with the present invention, intelligence to control data transfer and to schedule access to the bus is distributed throughout the system. Some of this scheduling intelligence is included in the bus arbiter, but the remainder is contained in several devices themselves.