Runtime Adapter Translation Format Determination
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Solution Overview
Problem
Existing systems for accessing system memory in computing environments face challenges in efficiently translating addresses from various components, such as central processing units and adapters, due to the lack of a one-to-one correspondence between virtual or PCI addresses and physical memory locations, requiring complex address translation mechanisms.
Innovation Solution
A computer program product that facilitates memory access by using a Modify PCI Function Controls (MPFC) instruction to determine and set a translation format for adapters, allowing for the generation of direct memory access (DMA) addresses based on pre-registered translation formats, thereby bypassing or optimizing the need for address translation tables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If address translation is performed using traditional methods with translation tables, then address translation accuracy is improved, but memory access time increases and system performance deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-registering translation formats for adapters during system initialization or configuration phases. The MPFC instruction allows the system to pre-establish translation format associations with adapter handles, so that during runtime, the appropriate translation format is already determined and stored, eliminating the need for complex runtime translation table lookups and reducing memory access time while maintaining translation accuracy
2Adaptability or versatility
If complex address translation mechanisms are used to handle virtual and PCI addresses, then address translation capability is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by introducing a translation format parameter that can be dynamically selected and stored in the device table entry. The MPFC instruction modifies the translation format parameter associated with an adapter handle, allowing the system to switch between different translation formats (such as direct mapping, windowing, or translation table-based mapping) based on the specific adapter requirements, thereby maintaining versatile address translation capability while simplifying the actual translation mechanism through parameterization
3Adaptability or versatility
If translation format is determined at runtime for each memory access, then adaptability is improved, but processing overhead increases
Solution Approach 1:
The patent resolves this contradiction by performing the translation format determination in advance through the MPFC instruction, which sets the translation format as a pre-configured parameter in the device table entry. During runtime memory access operations, the previously determined translation format is directly applied without requiring re-evaluation or complex selection logic, thus maintaining adaptability while eliminating processing overhead and preserving high memory access throughput
Data Source
AI summary
Various address translation formats are available for use in obtaining system memory addresses for use by requestors in accessing system memory. The particular address translation format to be used by a given requestor, an example of which is an adapter function, is pre-registered in a device table entry associated with that requestor.