Traversal Stack Compression for Ray Tracing Memory Bandwidth
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Solution Overview
Problem
Conventional traversal stacks in ray tracing and other operations consume a large portion of available memory bandwidth due to memory traffic, as each node is stored individually, leading to inefficient memory usage and performance.
Innovation Solution
A method for performing traversal stack compression by creating stack entries that contain multiple intersected nodes and storing them in a compressed format, reducing memory usage and traffic by representing multiple nodes as a single entry, thereby increasing available processing memory bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional traversal stacks store each node individually, then node access is simple and direct, but memory bandwidth consumption increases significantly
Solution Approach 1:
The patent merges multiple individual node storage operations into a single batched traversal stack entry. Instead of pushing each intersected node separately onto the traversal stack, the system accumulates multiple node indices and pushes them as a single batched entry, reducing memory transaction overhead while maintaining traversal functionality
Solution Approach 2:
The patent changes the parameter of stack entry structure from individual node storage to batched node storage. Each traversal stack entry contains multiple node indices packed together, transforming the data structure from fine-grained individual nodes to coarse-grained batches, thereby reducing memory bandwidth consumption
2Device complexity
If individual nodes are stored in the traversal stack, then memory access patterns are simple, but memory traffic consumes a large portion of available bandwidth
Solution Approach 1:
The patent combines multiple node push operations into a single batched push operation. The traversal stack processes nodes in batches rather than individually, merging multiple memory write operations into one transaction, which simplifies the overall memory access pattern while increasing processing efficiency by reducing memory traffic overhead
3Quantity of substance
If multiple nodes are stored as a single stack entry, then memory consumption and traffic are reduced, but the structure of stack entries becomes more complex
Solution Approach 1:
The patent segments the batched node data into fixed-size groups that fit within single memory transactions. By dividing the batched node indices into manageable segments that align with memory transaction boundaries, the system reduces memory traffic while keeping the stack entry structure relatively simple and predictable
Data Source
AI summary
A method, computer readable medium, and system are disclosed for performing traversal stack compression. The method includes traversing a hierarchical data structure having more than two children per node, and during the traversing, creating at least one stack entry, utilizing a processor, where each stack entry contains a plurality of intersected nodes, and adding the at least one stack entry to a compressed traversal stack stored in a memory, utilizing the processor.