RAM Module Chip-Select Segmentation for Single-Word Access
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Solution Overview
Problem
Existing memory modules with common chip select configurations limit memory access to full memory lines, leading to inefficient utilization of bandwidth for irregular and high spatial locality memory workloads.
Innovation Solution
Individual control of RAM chips within a memory channel allows for distinct, multiple single-word memory accesses, enabling flexible access to subsets of memory lines and reducing the need to open multiple memory pages simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common chip select configuration is used for all RAM chips in a memory module, then the memory module can be controlled with a single chip select signal, but memory access is limited to full memory lines resulting in inefficient bandwidth utilization
Solution Approach 1:
The memory module divides the common chip select signal into multiple individual chip select signals, one for each RAM chip. This segmentation allows independent control of each chip, enabling selective access to single data words rather than requiring access to entire memory lines, thus improving bandwidth utilization for irregular and high spatial locality workloads
2Productivity
If individual chip select signals are provided for each RAM chip, then flexible access to single data words is enabled improving bandwidth utilization, but the control complexity of the memory module increases
Solution Approach 1:
A chip select decoder circuit is introduced as an intermediary component that receives a reduced number of control signals and generates the appropriate individual chip select signals for each RAM chip. This decoder mediates between the simplified control interface and the detailed chip-level control requirements, reducing overall control complexity while maintaining flexible single-word access capability
3Ease of operation
If full memory line access is required for each memory operation, then simpler control logic is needed, but memory access latency increases for workloads that only need single data words
Solution Approach 1:
The memory access operation is segmented at the chip level, allowing the control logic to selectively activate only the specific RAM chip containing the required data word. This segmentation enables precise targeting of memory locations, reducing access latency for workloads that need only single data words while maintaining relatively simple control logic through the use of individual chip select signals
4Productivity
If multiple memory pages must be opened simultaneously to access scattered data words, then more data can be accessed in parallel, but memory resource consumption increases
Solution Approach 1:
The memory module implements fine-grained segmentation at the chip and word level through individual chip select signals. This allows the system to access multiple scattered data words by selectively activating only the specific RAM chips containing those words, rather than opening entire memory pages. This segmentation reduces memory resource consumption while maintaining parallel access capability for irregular workloads
Data Source
AI summary
Memory modules with random access memory (RAM) chips supporting distinct, multiple single-word memory accesses, and related memory systems and methods of performing memory accesses to such memory modules are disclosed. To avoid the memory module only having a full memory line resolution for a memory access, the memory module supports individually controlled access to each RAM chip. For example, a separate chip select can be provided for each RAM chip so that each RAM chip can be individually and selectively enabled. In this manner, a memory access can be performed to a specific RAM chip for memory accesses at a single data word resolution to allow higher data utilization of the memory module. This is opposed to memory accesses being limited to a full memory line resolution in the memory module. The IMM can be provided as a single IMM (SIMM) package or dual IMM (DIMM) package, as examples.