Sun Microsystems, Inc.

Oracle America, Inc.

Magnus Ekman

Per O Stenström

A method and apparatus for compressing data automatically selects either direct compression of sub-blocks or of compression of transformed sub-blocks to achieve fast and effective data compression. A method and apparatus for decompression automatically performs either direct decompression or decompression and transform operations for respective sub-blocks.

Method and apparatus for data compression and decompression

An approach for improving efficiency of speculative execution of instructions is disclosed. In one embodiment, a branch predictor entry associated with a particular branch instruction is accessed when the particular branch instruction is to be speculatively executed. The branch predictor entry may take on different values indicating whether a first possible path or a second possible path should be executed. Based upon a current value of the branch predictor entry, a predicted path for the particular branch instruction may be determined. Instructions along the predicted path may be executed, before the particular branch instruction is resolved. Once the particular branch instruction is resolved, a cost associated with executing the one or more instructions may be determined. Accordingly, the branch predictor entry may be updated by an amount that is commensurate with the cost.

Branch predictor for branches with asymmetric penalties

A computing system comprises a processor, a data storage unit, and a block size table (BST). The processor includes at least one cache configured to store data. The data storage unit is configured to store data in a compressed format in fixed size units. The BST is configured to store block size entries corresponding to data blocks stored in the data storage unit. In response to a miss in the cache corresponding to a target data block, the processor is configured to identify an entry in the BST corresponding to the target data block, utilize information stored in the entry to determine the location of the target data block in the data storage unit, and cause the target data block to be retrieved from the data storage unit, decompressed, and stored in the cache.

System and method for memory compression

A method and apparatus for compressing uncompressed data by applying a transform prior to the application of a data compression scheme. At decompression time, a transform can be applied after a data decompression scheme has been applied to compressed data.

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San Francisco, CA, United States of America

Magnus Ekman