Techniques for dynamically compressing memory regions having a uniform value

Abstract

The invention discloses techniques for dynamically compressing memory regions having a uniform value. Accesses between a processor and its external memory is reduced when the processor internally maintains a compressed version of values stored in the external memory. The processor can then refer to the compressed version rather than access the external memory. One compression technique involves maintaining a dictionary on the processor mapping portions of a memory to values. When all of the values of a portion of memory are uniform (e.g., the same), the value is stored in the dictionary for that portion of memory. Thereafter, when the processor needs to access that portion of memory, the value is retrieved from the dictionary rather than from external memory. Techniques are disclosed herein to extend, for example, the capabilities of such dictionary-based compression so that the amount of accesses between the processor and its external memory are further reduced.

Description

technical field [0001] The present disclosure relates to dictionary-based compression, and more particularly, to scalable dictionary-based compression. Background technique [0002] Conventionally, the Zero Bandwidth Clear (ZBC) command is used to associate a single value with multiple locations in memory without actually writing the value to each memory location. This association is done by storing a single value (called a uniform value) in a global uniform table at a particular index in the table, and associating that index with multiple memory locations. Thereafter, when a value needs to be read from one of the plurality of memory locations, the value is retrieved from the global uniform table using the index associated with that memory location. These memory locations are in off-chip memory, so actually reading values ​​from or writing values ​​to memory locations consumes memory access bandwidth. In contrast, the global unified table is usually stored on-chip. Thus, ...

AI Technical Summary

Problems solved by technology

However, existing ZBC mechanisms have at least two disadvantages

The performance of ZBC compression is limited by the capacity of the global unified table

When all entries have been used to store values, it is difficult (e.g., time-consuming) to reclaim or free any entries to store new values, even if no longer referencing a particular value in the table

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