Memory Read Cancel Commands for Speculative Access Congestion
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Solution Overview
Problem
Unused read commands in memory systems cause congestion, throughput overhead, and power consumption due to speculative data access, particularly in staggered memory refresh systems where data from certain memory modules is not needed by the host device.
Innovation Solution
Implementing a cancel command mechanism in the memory controller to identify and cancel unused read commands before they are processed by the memory device, using identifiers like CAPPTag to target specific operations, thereby preventing unnecessary access and resource consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If read commands are issued speculatively to reduce latency and anticipate future parallel read operations, then access speed is improved, but memory congestion increases and power consumption increases
Solution Approach 1:
The patent applies preliminary action by issuing read commands speculatively before the data is actually needed, anticipating future parallel read operations. This allows the memory system to prepare data in advance, reducing latency when the data is actually required while managing memory congestion through intelligent command cancellation
2Speed
If read commands are issued speculatively to reduce latency, then access speed is improved, but power consumption increases
Solution Approach 1:
The system performs preliminary read operations speculatively to reduce latency, but applies cancellation mechanisms (cancel commands with identifiers) to terminate speculative reads that are determined to be unused, thereby recovering power that would have been consumed for unnecessary memory access operations
Solution Approach 2:
The patent discards unused speculative read commands by issuing cancel commands when it is determined that the data will not be needed. This allows the system to recover power consumption that would have been wasted on unnecessary memory access operations while maintaining the performance benefits of speculative execution for needed data
3Ease of operation
If read commands are forwarded to memory buffer chip, then data access is enabled, but throughput overhead increases
Solution Approach 1:
The patent extracts and removes unused read commands from the memory system by implementing cancel command functionality at the memory controller. This prevents unnecessary commands from reaching the memory buffer chip, thereby eliminating throughput overhead while preserving the ability to access needed data efficiently
Data Source
AI summary
In some implementations, a controller may determine that a read response, to a read command of a plurality of read commands, has not been received from a memory device of a plurality of memory devices. The controller may provide a cancel command to the memory device to cause the memory device to cancel the read command based on determining that the read response, to the read command, has not been received from the memory device, wherein the cancel command is provided after read responses, to other read commands of the plurality of read commands, have been received from other memory devices of the plurality of memory devices, and wherein the cancel command includes an identifier associated with the read command.