Graphics Memory Page Pool Allocation for Ray Tracing Forward Progress
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Solution Overview
Problem
In graphics processing, managing resources for secondary threads, such as those involved in ray tracing, can lead to deadlock conditions due to insufficient memory pages, especially when primary threads depend on the completion of secondary threads, and existing solutions like dedicated page pools duplicate control circuitry and increase software interaction.
Innovation Solution
The implementation of a page pool with separate tracking for public and protected pages, where protected pages are reserved for secondary threads, and arbitration circuitry ensures forward progress by prioritizing protected page allocation and re-arbitrating resource allocations to avoid deadlocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated page pool is created for secondary threads, then forward progress for secondary threads is guaranteed, but control circuitry is duplicated and software interaction increases
Solution Approach 1:
The page pool is segmented into two distinct portions: a first portion for primary threads and a second portion for secondary threads. This segmentation ensures that secondary threads have dedicated memory resources guaranteed for their execution, preventing deadlock conditions while maintaining a unified memory architecture that avoids complete duplication of control circuitry.
2Productivity
If memory pages are allocated dynamically, then resource utilization is optimized, but deadlock conditions may occur when primary threads depend on secondary threads
Solution Approach 1:
The page pool is pre-configured with separate portions allocated for primary and secondary threads before execution begins. This preliminary allocation ensures that when secondary threads are launched, their required memory pages are already reserved, eliminating the need for dynamic allocation that could cause deadlocks while maintaining efficient resource utilization.
3Device complexity
If unified memory architecture is used, then resource management is simplified, but insufficient memory pages cause secondary threads to stall
Solution Approach 1:
Within the unified memory architecture, different portions of the page pool are assigned different qualities: the first portion serves primary threads and the second portion serves secondary threads. This local differentiation ensures that secondary threads receive guaranteed memory pages for their specific operations while maintaining the overall simplicity of unified memory management.
Data Source
AI summary
Techniques are disclosed relating to memory page allocation for graphics processor. In some embodiments, a shader program includes a primary thread associated with ray tracing (that includes an instruction that indicates for the apparatus to launch one or more secondary threads). Memory resource allocator circuitry may receive a request to allocate a memory page in a page pool to a thread of the shader program, where the page pool includes a set of protected pages and a set of public pages. The allocator may allocate a page of the page pool to the requesting thread according to an allocation restriction, such that protected pages are allocable only to secondary threads that are launched based on a primary thread and public pages are allocable to both primary and secondary threads.