US 7,412,555 B2Granted

Ordering rule and fairness implementation

AssigneeP.A. Semi, Inc.

InventorJames Wang

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Abstract

In one embodiment, a controller comprises one or more transaction queues, one or more age counter circuits, and a control circuit. The transaction queues are configured to store a plurality of transaction requests, each having a transaction type. The age counter circuits are configured to generate one or more age counters, where each age counter corresponds to a respective pair of transaction types. Coupled to receive an indication of an input transaction type corresponding to an input transaction request to the controller and coupled to the age counter circuits, the control circuit is configured to select at least one of the plurality of age counters to be stored with the input transaction request in the one or more transaction queues, each of the selected counters indicative of a relative age of the input transaction request with transaction requests of another transaction type.

Claims21

Dependent claims

A controller comprising:

one or more transaction queues storing, during use, a plurality of transaction requests, each of the plurality of transaction requests having a transaction type;
one or more age counter circuits generating, during use, one or more age counters, each of the age counters corresponding to a respective pair of transaction types;
and
a control circuit coupled to receive an indication of an input transaction type corresponding to an input transaction request to the controller and coupled to the one or more age counter circuits, wherein the control circuit selects at least one of the one or more age counters to be stored with the input transaction request in the one or more transaction queues, each of the at least one selected counters indicative of a relative age of the input transaction request with transaction requests of another transaction type, and wherein the control circuit conditionally causes, during use, an update of a first age counter for which the corresponding pair includes the input transaction type, wherein the control circuit does not cause the update responsive to the input transaction type being the same as the most recent transaction type of the corresponding pair, regardless of which of the corresponding pair is the input transaction type.

1 more element

A controller coupled to receive an input transaction request having an input transaction type that is one of a plurality of transaction types, the controller comprising:

at least one age counter circuit generates, during use, at least one age counter, the age counter corresponding to a pair of the plurality of transaction types and maintained to indicate a relative age of transaction requests having the pair of transaction types;
and
a control circuit coupled to the age counter circuit, wherein the control circuit updates, during use, the age counter responsive to the input transaction type being one of the pair of transaction types and further responsive to the input transaction type differing from a most recent transaction type of the pair, wherein the most recent transaction type corresponds to a most recent transaction request of transaction requests having one of the pair of transaction types, and wherein the control circuit does not update the age counter responsive to the input transaction type being the same as the most recent transaction type of the corresponding pair, regardless of which of the corresponding pair is the input transaction type.

A method comprising:

receiving an input transaction request having an input transaction type;
selecting one or more age counters, wherein each of the one or more age counters corresponds to a respective pair of transaction types;
storing the selected age counters with the input transaction request in one or more transaction queues, each of the selected age counters indicative of a relative age of the input transaction request with transaction requests of another transaction type;
determining whether or not the input transaction type is the same as a most recent transaction type of the pair of transaction types corresponding to a first age counter of the one or more age counters;
updating the first age counter responsive to the input transaction type different from the most recent transaction type;
and
not updating the first age counter responsive to the input transaction type being the same as the most recent transaction type of the corresponding pair, regardless of which of the corresponding pair is the input transaction type.

4 more elements

Dependencies are inferred from the claim text.