Front End Core TLB for Shared Virtual Memory Page Fault Handling
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Solution Overview
Problem
Current processor designs using shared virtual memory between the CPU and GPU suffer from inefficiencies in page fault handling, resulting in slower performance due to driver-based mechanisms that involve significant CPU overhead and treat page faults differently from regular exceptions.
Innovation Solution
Implementing a lightweight front end core that acts as a memory management unit for accelerators, utilizing a translation lookaside buffer (TLB) and page walker module to handle page faults natively, and incorporating a TLB shootdown handler to manage access permissions, thereby reducing CPU overhead and leveraging native OS virtual memory support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If driver-based page fault handling mechanisms are used for GPU memory management, then memory management functionality is provided, but CPU overhead increases significantly and performance decreases
Solution Approach 1:
A front end core is introduced as an intermediary component between the GPU and the CPU. This front end core includes a translation lookaside buffer (TLB) and page walker module that handle page fault management locally, acting as a mediator that prevents direct CPU involvement in routine page fault operations while maintaining proper memory management functionality.
Solution Approach 2:
The GPU system is enhanced with self-service capabilities through the front end core, which autonomously handles page fault detection, TLB management, and page walker operations. This allows the system to manage its own memory access faults without requiring continuous CPU intervention, thereby reducing CPU overhead and improving handling performance.
2Productivity
If native OS virtual memory support is implemented through front end core, then CPU overhead is reduced, but device complexity increases
Solution Approach 1:
The memory management functionality is segmented into distinct modular components: a front end core, translation lookaside buffer (TLB), and page walker module. This segmentation allows each component to perform its specific function independently, making the overall complex system more manageable and maintainable while enabling efficient native OS virtual memory support.
Data Source
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AI summary
An apparatus and method are described for coupling a front end core to an accelerator component (e.g., such as a graphics accelerator). For example, an apparatus is described comprising: an accelerator comprising one or more execution units (EUs) to execute a specified set of instructions; and a front end core comprising a translation lookaside buffer (TLB) communicatively coupled to the accelerator and providing memory access services to the accelerator, the memory access services including performing TLB lookup operations to map virtual to physical addresses on behalf of the accelerator and in response to the accelerator requiring access to a system memory.