Host Bus Adapter DMA Descriptor Segmentation for Throughput
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The performance of host bus adapters in data storage systems, such as the IBM DS8000 enterprise storage system, is limited by inefficiencies in executing complex DMA transfer operations, leading to increased processor overhead and reduced data throughput.
Innovation Solution
A method is introduced that generates a DMA descriptor with specific fields to perform operations like echo read, dual write, and loop DDs, allowing the DMA engine to efficiently execute these operations with fewer descriptors and runs, thereby improving data transfer efficiency through the host bus adapter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional DMA transfer methods are used, then the host bus adapter can perform data transfers, but the processor overhead increases and data throughput decreases for complex operations
Solution Approach 1:
The patent segments complex DMA operations into distinct operational types (echo read, dual write, loop DDs, normal DMA transfer) and represents each segment in a single descriptor field. This segmentation allows the DMA engine to efficiently handle each operation type without requiring multiple separate descriptors, thereby reducing processor overhead while maintaining high data throughput.
Solution Approach 2:
The patent changes the parameter representation in DMA descriptors by incorporating an operation type field that specifies the kind of transfer operation. This parameter change enables the DMA engine to automatically adjust its behavior based on the operation type, eliminating the need for multiple descriptors and reducing processor intervention, thus improving productivity while reducing time loss.
2Adaptability or versatility
If multiple DMA descriptors are used to handle complex operations, then operational flexibility is maintained, but device complexity and processing overhead increase
Solution Approach 1:
The patent implements a universal DMA descriptor structure that can handle multiple operation types (echo read, dual write, loop DDs, normal DMA transfer) within a single descriptor. The operation type field enables this multi-functionality, allowing one descriptor to replace multiple specialized descriptors, thereby maintaining operational flexibility while reducing device complexity and processing overhead.
Solution Approach 2:
The patent merges multiple operation types into a single DMA descriptor by combining the operation type specification with the transfer parameters in one unified structure. This merging eliminates the need for separate descriptors for different operation types, reducing descriptor complexity while preserving the ability to handle diverse operations flexibly.
Data Source
AI summary
A method for improving performance of a direct memory access (DMA) transfer is disclosed. The method generates a descriptor that describes parameters of a DMA transfer to be performed by a DMA engine, such as a DMA engine within a host bus adapter of a data storage system. The method provides, in the descriptor, a field that describes an operation to be performed by the DMA engine. The field has as options an echo read operation, a dual write operation, a loop DDs operation, and a normal DMA transfer operation. The method provides the descriptor to the DMA engine. The DMA engine extracts the operation from the field and performs the operation. This operation may, in certain embodiments, move data through a host bus adapter of a data storage system. A corresponding system and computer program product are also disclosed.