Memory-Side Controller Capability Interpretation for Latency Reduction
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Solution Overview
Problem
Computers with multi-layer memory hierarchies face increased memory access latency due to pointer-intense workloads, as traditional memory operations are executed inside the CPU, leading to inefficiencies in accessing distant memory layers.
Innovation Solution
Implementing a memory-side memory controller that translates virtual addresses to physical addresses and interprets capabilities to directly dereference pointers within the memory controller, reducing the number of memory accesses by executing operations on the memory side and using capabilities for fine-grained memory access control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If memory operations are executed inside the CPU with traditional memory hierarchy, then memory access control and management are centralized, but memory access latency increases significantly when accessing distant memory layers
Solution Approach 1:
The patent extracts pointer interpretation and capability validation functions from the CPU to the memory controller. The memory controller now independently interprets capabilities and performs pointer dereferencing, removing these operations from the CPU execution path and reducing memory access latency while maintaining centralized control.
Solution Approach 2:
The patent introduces capabilities as intermediary data structures that enable the memory controller to perform fine-grained access control without CPU intervention. These capabilities act as mediators between the CPU's memory requests and the memory system, allowing the memory controller to autonomously validate and execute access operations.
2Loss of time
If the memory controller autonomously interprets capabilities and dereferences pointers, then memory access latency is reduced, but the device complexity of the memory controller increases
Solution Approach 1:
The patent segments the memory access function into distinct components: capability validation, pointer interpretation, and memory access execution. These segmented functions are implemented as separate modules within the memory controller, making the increased complexity manageable and organized while enabling parallel processing of different access operations.
Solution Approach 2:
The patent implements preliminary capability validation and interpretation in the memory controller before actual memory access occurs. By pre-processing capability information and validating access permissions ahead of time, the system reduces the complexity of real-time access control while maintaining security and correctness.
3Reliability
If capabilities are used for fine-grained memory access control, then security and access protection are enhanced, but the processing overhead for capability interpretation increases
Solution Approach 1:
The patent enables the memory controller to autonomously validate and interpret capabilities without CPU intervention. The memory controller self-services the capability interpretation process, using dedicated hardware logic to validate access permissions and dereference pointers, thereby maintaining security while avoiding the processing overhead of CPU involvement.
Solution Approach 2:
The patent replaces software-based capability interpretation (which would require CPU processing) with hardware-based interpretation logic in the memory controller. This substitution of mechanical/hardware processing for software processing maintains fine-grained access control while significantly improving processing throughput by eliminating software overhead.
Data Source
AI summary
Methods and systems directed to a memory-side memory controller for interpreting capabilities and returning datasets to a Central Processing Unit (CPU) are provided. The CPU is configured to translate a first virtual address from a first capability to a first physical address, wherein the first capability is sent by a client application. The CPU is further configured to send the first physical address to the memory-side memory controller through a memory fabric. The memory-side memory controller loads a second capability located in the first physical address from an external memory through the memory fabric, interprets an address encoded within the second capability as a second physical address, and returns a dataset located in the second physical address from the external memory to the CPU through the memory fabric. The client application may set an offset field containing an offset parameter along with the first capability, and the memory-side memory controller may be configured to read the offset field and apply the offset parameter when loading the second capability from the external memory. The computing system may also include a mechanism to validate a capability, such as a validity bit or cryptographic signature.