Writeback Control for Read-Destructive Memory
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Solution Overview
Problem
Conventional writeback mechanisms in read-destructive computer memory, such as DRAM, result in unnecessary energy consumption by writing back data that will not be reused, leading to increased power dissipation and reduced battery life in portable devices.
Innovation Solution
A method and memory-control logic that determine a discard state for data stored in a row of computer memory based on its usage, where a positive discard state indicates data to be read only once and a negative state indicates data to be read more than once, thereby judiciously controlling writeback operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is written back to read-destructive computer memory after every read operation, then data integrity is preserved for future reads, but energy consumption increases unnecessarily for data that will not be reused
Solution Approach 1:
The patent changes the parameter of writeback operation from a fixed always-on mode to a dynamic mode controlled by a discard state parameter. The memory controller modifies its behavior based on the discard state indicator, enabling writeback only when necessary (when discard state indicates data will be reused) and skipping writeback when unnecessary (when discard state indicates data will not be reused), thus resolving the contradiction between data integrity and energy consumption
Solution Approach 2:
The system uses self-service by having the host processor or memory controller automatically track and indicate the reuse status of data through the discard state parameter. This eliminates the need for continuous writeback operations by allowing the system to self-manage data preservation based on actual usage patterns, reducing energy consumption while maintaining data integrity when needed
2Duration of action of stationary object
If writeback operations are performed frequently to preserve data in read-destructive memory, then data can be read multiple times, but power dissipation increases and battery life decreases
Solution Approach 1:
The patent introduces a discard state parameter that dynamically controls writeback operations. When the discard state indicates data will be reused, writeback is performed to preserve data for future reads. When the discard state indicates data will not be reused, writeback is skipped, avoiding unnecessary energy loss. This parameter-based control resolves the contradiction between data reusability and power dissipation
Solution Approach 2:
The patent applies partial action by performing writeback operations only partially - specifically, only for data that will be reused according to the discard state indicator. Instead of universally writing back all read data (excessive action), the system selectively writes back only the necessary portion, thereby reducing power dissipation while maintaining data reusability where needed
Data Source
AI summary
A method comprises receiving a read instruction and determining a read address in computer memory corresponding to the read instruction, where the read address references a cell within a row of read-destructive computer memory. The method further comprises determining a discard state for data stored in the row according to a usage of the data, the discard state being positive for data to be read only once and negative for data to be read more than once. The data is read from the row and written back to the row if the discard state is negative. If the discard state is positive, then the method returns without writing the data back to the row.