Streaming Engine Address Translation for Sequential Data Throughput
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Modern digital signal processors face challenges such as increasing workloads, memory system latency, and reliability issues due to smaller transistors, which affect memory bandwidth and scheduling, especially in real-time data processing applications.
Innovation Solution
A streaming engine is employed in a digital signal processor to manage data streams efficiently. This engine includes an address generator, a stream head register, and an address translation unit that handles virtual to physical address translation, allowing for efficient operand fetching and data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If virtual address translation is performed for each sequential address in a data stream, then address translation accuracy is improved, but processing time increases and throughput decreases
Solution Approach 1:
The patent performs address translation in advance by translating a range of sequential addresses (N through N+7) simultaneously rather than translating each address individually when needed. This preliminary batch translation stores results in the μTLB, allowing subsequent address accesses within this range to be resolved quickly without repeated translation operations, thus maintaining accuracy while improving throughput.
Solution Approach 2:
The patent translates more addresses than immediately necessary by performing batch translation of sequential address ranges. This excessive action translates addresses N through N+7 even though only address N may be needed immediately, but this approach amortizes the translation cost across multiple subsequent accesses and improves overall stream throughput.
2Productivity
If batch address translation of sequential addresses is performed, then data stream throughput is improved, but memory bandwidth consumption increases
Solution Approach 1:
The patent combines multiple address translation operations into a single batch operation. Instead of making separate memory accesses for translating each address individually, the system merges these operations into one unified batch translation process, reducing the total number of memory accesses and optimizing memory bandwidth utilization.
3Speed
If address translation is optimized for sequential addresses, then processing speed is improved, but system complexity increases
Solution Approach 1:
The patent segments the address translation process into distinct phases: batch translation of sequential address ranges, selective translation of non-sequential addresses, and result caching in the μTLB. This segmentation allows the system to optimize for sequential access patterns while maintaining handling capability for non-sequential addresses, improving speed without excessive complexity.
Data Source
AI summary
A streaming engine employed in a digital data processor specifies a fixed read only data stream. An address generator produces virtual addresses of data elements. An address translation unit converts these virtual addresses to physical addresses by comparing the most significant bits of a next address N with the virtual address bits of each entry in an address translation table. Upon a match, the translated address is the physical address bits of the matching entry and the least significant bits of address N. The address translation unit can generate two translated addresses. If the most significant bits of address N+1 match those of address N, the same physical address bits are used for translation of address N+1. The sequential nature of the data stream increases the probability that consecutive addresses match the same address translation entry and can use this technique.