Method and apparatus for efficiently tracking queue entries relative to a timestamp

摘要

An apparatus and method for tracking coherence event signals transmitted in a multiprocessor system. The apparatus comprises a coherence logic unit, each unit having a plurality of queue structures with each queue structure associated with a respective sender of event signals transmitted in the system. A timing circuit associated with a queue structure controls enqueuing and dequeuing of received coherence event signals, and, a counter tracks a number of coherence event signals remaining enqueued in the queue structure and dequeued since receipt of a timestamp signal. A counter mechanism generates an output signal indicating that all of the coherence event signals present in the queue structure at the time of receipt of the timestamp signal have been dequeued. In one embodiment, the timestamp signal is asserted at the start of a memory synchronization operation and, the output signal indicates that all coherence events present when the timestamp signal was asserted have completed. This signal can then be used as part of the completion condition for the memory synchronization operation.

主权项

1. An apparatus for tracking event signals transmitted in a multiprocessor system having a plurality of processor devices, said apparatus comprising:
a queue structure for storing said event signals transmitted in said system; a logic device associated with said queue structure for controlling enqueuing and dequeuing of received said event signals at said structure; and, a counting mechanism for tracking a number of event signals remaining enqueued in said queue structure and dequeued since receipt of a timestamp signal, and, said counting mechanism generating an output signal indicating that all of the event signals present in the queue structure at the time of receipt of said timestamp signal have been dequeued.