Reverse Thread Dispatch for Graphics Cache Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current graphics processing systems face inefficiencies in cache utilization due to the sequential execution of threads, leading to increased memory bandwidth requirements and latency, particularly in scenarios where producer and consumer operations have a large data working set that exceeds cache capacity.
Innovation Solution
The proposed solution involves modifying the thread dispatch order to execute threads in a reverse sequence, ensuring that data produced by one operation is still resident in the cache when consumed by subsequent operations, thereby optimizing cache and shared local memory usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If threads are executed in sequential order, then program simplicity is maintained, but cache efficiency deteriorates and memory bandwidth consumption increases
Solution Approach 1:
The patent inverts the traditional thread execution order by implementing reverse chronological scheduling. Instead of executing threads in the order they are submitted (first-in-first-out), the system executes them in reverse order (last-in-first-out). This inversion allows data produced by later threads to remain in cache when earlier threads need to consume it, dramatically improving cache efficiency and reducing memory bandwidth consumption without adding significant system complexity
2Device complexity
If threads are executed in sequential order, then implementation simplicity is maintained, but latency increases due to repeated memory accesses
Solution Approach 1:
By reversing the thread execution sequence, the patent ensures that data flows through the cache in an optimized pattern. Data produced by consumer operations remains in cache when producer operations need to access it, eliminating repeated memory accesses and reducing processing latency while maintaining a relatively simple scheduling mechanism
3Productivity
If data working set exceeds cache capacity with sequential thread execution, then memory operations are performed, but power consumption increases
Solution Approach 1:
The reverse chronological scheduling ensures that when the data working set exceeds cache capacity, data is accessed in an order that maximizes cache hits. By executing threads in reverse order, the system keeps frequently accessed data in cache longer, reducing the need for high-power memory accesses and thereby reducing overall power consumption while maintaining data processing throughput
Data Source
AI summary
Systems and methods for scheduling thread order to improve cache efficiency are disclosed. In one embodiment, a graphics processor includes processing resources and schedule and dispatch logic to schedule and dispatch threads to the processing resources. The schedule and dispatch logic is configured to receive threads, to schedule and dispatch the threads based on a forward thread dispatch having a forward thread order, and to determine whether to disable a reversing of a thread order upon completion of at least a portion of the forward thread dispatch including a completion or ending of a draw call or a dispatch.