Global Virtual Address Directory for NVM Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current distributed shared memory systems face challenges in directly accessing Non-Volatile Memory (NVM) technologies like SCM and remote memories due to bandwidth and latency issues, preventing them from appearing as normal system memory, and existing cache designs are inadequate for covering the latency of these systems.
Innovation Solution
The approach identifies a 'home' node for data granules within an information handling system by using a global virtual address directory to map shared virtual addresses to nodes, allowing direct access to data granules, and dynamically updates ownership and location of data granules across nodes, enabling efficient access and relocation within the Global Virtual Address Space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct access to SCM and remote memories is attempted using processor load and store instructions, then memory accessibility is improved, but bandwidth and latency characteristics prevent successful direct access
Solution Approach 1:
The patent introduces a global virtual address directory as an intermediary structure that maps shared virtual addresses to home nodes. This directory acts as a mediator between the processor and remote memory systems, enabling indirect access that overcomes the bandwidth and latency limitations of direct access attempts. The directory structure allows the system to manage remote memory access through virtual address translation rather than direct physical addressing.
Solution Approach 2:
The patent replaces the traditional mechanical direct access mechanism (processor load/store instructions directly to physical memory addresses) with a software-based virtual address translation mechanism. This substitution allows the system to manage memory access through virtual address mapping and home node identification rather than direct physical addressing, effectively working around the hardware limitations of SCM and remote memory bandwidth and latency characteristics.
2Reliability
If traditional cache designs are used to cover system memory latency, then cache effectiveness is maintained, but caches are not effective for SCM or remote node memory
Solution Approach 1:
The patent creates a universal address mapping mechanism that works across multiple memory types including system memory, SCM, and remote node memory. The global virtual address directory provides a unified interface for accessing different memory technologies, making the memory subsystem universally accessible through the same virtual address translation mechanism regardless of the underlying physical memory technology being used.
3Adaptability or versatility
If virtual address to node translation is performed all in software, then flexibility is improved, but access speed deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-establishing the global virtual address directory structure and pre-determining home node mappings for virtual addresses. This preliminary setup allows subsequent memory access operations to use pre-computed mappings rather than performing full software-based translation each time, significantly improving access speed while maintaining the flexibility of virtual address management.
Data Source
AI summary
An approach is disclosed that identifies a home node of a data granule. The process is performed by an information handling system (a local node) that retrieves a global virtual address directory. The global virtual address directory maps shared virtual addresses to a number nodes that includes the local node with one of the nodes being the home node. The shared virtual addresses correspond to a plurality of memory addresses that are stored in a shared virtual memory that is shared amongst the plurality of nodes. The approach receives a selected shared virtual address, retrieves, from the global virtual address directory, the home node associated with the selected shared virtual address, and accesses the data granule corresponding to the selected shared virtual address from the home node.