Method and apparatus for efficiently tracking queue entries relative to a timestamp
First Claim
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.
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Abstract
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.
110 Citations
21 Claims
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1. An apparatus for tracking event signals transmitted in a multiprocessor system having a plurality of processor devices, said apparatus comprising:
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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. - View Dependent Claims (2, 3, 11, 13, 20)
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- 4. An apparatus as claimed in Claim I, wherein said event signals are coherence event signals, and said queue structure is a coherence logic unit associated with each processor of said multiprocessor system.
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14. A method for tracking event signals transmitted in a multiprocessor system, said method comprising:
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intercepting an event signal in said multiprocessor system; enqueuing and dequeuing intercepted said event signals at a queue structure; counting a number of event signals enqueued in said queue structure and dequeued from said queue structure since receipt of a timestamp signal; generating an output signal indicating that all of the event signals present in the queue structure at the time of receipt of the timestamp signal have been dequeued; controlling said enqueuing and dequeuing intercepted said event signals by generating a respective enqueue signal for receipt at said queue structure for controlling input of said intercepted event signal in said queue structure and a dequeue signal for receipt at said queue structure for controlling said dequeuing of said event signal from said queue structure, wherein said counting a number of said event signals enqueued and dequeued from said queue structure includes; implementing a first counter device responsive to assertion of said enqueue signal and dequeue signal for counting a number of enqueued event signals in said queue structure; implementing a second counter device responsive to receipt of said timestamp signal for receiving a count signal representing said number of enqueued event signals presently in said queue structure; and counting down from said number in response to assertion of each dequeue signal asserted when removing said enqueued event signal from said queue structure, said second counter device generating said output signal when it counts down to zero. - View Dependent Claims (15, 21)
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16. A queue logic unit for tracking a plurality of event signals in a multiprocessor system, said unit comprising:
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a queue structure for storing said coherence event signals transmitted in said system; a logic device associated with a queue structure for controlling enqueuing and dequeuing of received said event signals at said structure; and
,a counter mechanism for tracking a number of event signals remaining enqueued in said queue structure and dequeued since receipt of a timestamp signal, and, said counter mechanism generating an output signal indicating that all of the event signals present in the queue structure at the time of receipt of the timestamp signal have been dequeued. - View Dependent Claims (17, 18, 19)
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Specification