Cisco Technology, Inc.

Pensando Systems Inc.

Alex Seibulescu

Sarang M Dharmapurikar

Wanli Wu

Kit Chiu Chu

Ganlin Wu

Described are input output (IO) device configured to perform operations for performing a table lookup with a single wide key larger than a width of a system bus. These operations comprise: receiving the lookup key; performing a plurality of extraction cycles to determine a plurality of key fragments; calculating a final hash value for the lookup key by sequentially calculating, via a hash chain, an interim hash value for each of the key fragments; determine a read access address for a table entry of a logic table based on the final hash value for the lookup key; determine a plurality of read requests based on the read access address; determine a hit on the table entry with the lookup key by issuing each of the read requests to the memory subsystem; and provide the hit on the table entry to the requesting entity or a next processing entity.

Method to perform hash table lookup for keys wider than data path size

According to one aspect, a method includes determining whether at least one memory storage unit in a first stage of a multi-stage array is available for use by a first counter associated with the first stage, and allocating the at least one memory storage unit for use by the first counter when the at least one memory storage unit is available. When the at least one memory storage unit is not available for use by the first counter, the method includes identifying a second counter stored in a first location in the first stage, the first location including a first memory storage unit and a second memory storage unit, and moving the second counter to a second stage of the multi-stage array, storing a pointer to the second stage in the first memory storage unit, and allocating the second memory storage unit to the first counter.

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San Mateo, CA, United States of America

Alex Seibulescu