Physical Attribute Table for NUMA Memory Access Tracking
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Solution Overview
Problem
Current processor architectures lack the ability to provide dynamic memory access information to software and hardware, hindering optimal data placement and migration in non-uniform memory access (NUMA) systems, and they suffer from security gaps in device access mechanisms.
Innovation Solution
A Physical Attribute Table (PAT) is introduced to track attributes for physical memory pages, including read, write permissions, access counts, and control attributes, to guide data movement and access permissions, and prevent unauthorized access by limiting translated memory accesses to well-defined physical addresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If current processor architectures are used without additional tracking mechanisms, then device complexity is low, but memory access optimization and data placement capability are insufficient
Solution Approach 1:
The patent introduces a Physical Attribute Table (PAT) as an intermediary structure between the processor and memory system. The PAT tracks physical address accesses and provides memory access information to software and hardware, enabling optimized data placement and migration decisions without fundamentally changing the processor architecture. This mediator approach allows the system to gain adaptability while keeping the core processor design relatively simple.
Solution Approach 2:
The patent implements feedback mechanisms where the PAT continuously monitors and tracks physical address accesses, providing real-time memory access information back to the system. This feedback enables dynamic data placement and migration decisions based on actual access patterns, improving memory access optimization through informed decision-making while maintaining manageable system complexity.
2Productivity
If dynamic memory access tracking is implemented, then data placement optimization improves, but device complexity increases
Solution Approach 1:
The PAT serves as an intermediary tracking structure that monitors physical address accesses without requiring complex modifications to the processor itself. By placing the tracking functionality in a separate table structure, the system achieves improved data placement efficiency while isolating the complexity to a manageable component rather than distributing it throughout the entire processor architecture.
Solution Approach 2:
The patent segments the memory tracking function into a separate Physical Attribute Table structure, distinct from the core processor operations. This segmentation allows the tracking functionality to be implemented independently, improving data placement efficiency through specialized tracking while keeping the overall system complexity manageable by separating concerns into discrete, independent components.
3Loss of information
If access tracking is implemented for all memory locations, then memory access information completeness improves, but loss of time due to tracking overhead increases
Solution Approach 1:
The patent implements selective tracking where the PAT monitors physical address accesses at specific critical locations and for specific types of accesses rather than uniformly tracking all memory operations. This local quality approach ensures complete information is captured where needed for optimization decisions while reducing tracking overhead in less critical areas, balancing information completeness with time efficiency.
Data Source
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AI summary
A system for tracking memory access patterns to be used in making data placement and migration policies. The system includes a processing unit and a system memory. The system memory includes a local memory and a remote memory, each of which having mapped thereon, a plurality of memory pages. Each of the plurality of memory pages corresponds to one or more physical addresses. A set of attributes for each memory page is stored in a physical attribute table (PAT). The PAT is looked up and the attributes updated when a memory access is detected. Attributes stored in the PAT are used to control the movement of memory pages between the local memory and the remote memory. When the attributes in the PAT indicate a remote memory page is being accessed frequently by the processing unit, the remote memory page is moved from the remote memory to the local memory.