PCIe Data Transfer Alignment for 4-kB Boundary Compliance
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Solution Overview
Problem
Existing data transfer technologies across PCIe switches face issues with 4-kB boundary crossing, leading to violations of the PCIe standard when data transfer starts slightly before a 4-kB boundary, requiring complex control mechanisms.
Innovation Solution
A data transfer device that includes a metadata creation section to manage transfer packets and a data transmission section that sets a write address to simulate a 4-kB boundary, ensuring data is transferred without crossing this boundary, using a compressor and decompressor to handle data in predetermined sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If data transfer is conducted in bytes with division into 1024 types of lower level addresses, then transfer packets can be divided at 4-kB boundary, but control becomes complicated
Solution Approach 1:
The patent changes the address parameter from byte-level granularity to 4-kB aligned boundaries. Instead of managing 1024 types of lower level addresses (0x0 to 0xFFC), the system now operates with alignment to 4-kB boundaries, simplifying the address space and control logic while maintaining precise boundary alignment for PCIe standard compliance
Solution Approach 2:
The patent segments the address space into 4-kB aligned blocks. By dividing the address space at 4-kB boundaries rather than at byte level, the system reduces the complexity of address management while ensuring that data transfers do not cross PCIe boundary violations, effectively segmenting the problem into manageable aligned blocks
2Productivity
If data transfer start position lies slightly before a 4-kB boundary, then data transfer can proceed, but PCIe standard is violated due to boundary crossing
Solution Approach 1:
The patent applies preliminary action by pre-calculating and adjusting the data transfer start position to align with 4-kB boundaries before initiating the transfer. The alignment processing unit proactively modifies the start address to ensure it falls on a valid 4-kB boundary, preventing boundary crossing violations before they can occur during data transfer
Solution Approach 2:
The patent introduces an alignment processing unit as an intermediary between the data source and the PCIe transfer mechanism. This intermediary component receives the original start address, adjusts it to the nearest valid 4-kB boundary, and passes the aligned address to the transfer engine, thereby mediating between arbitrary data positions and PCIe boundary requirements
Data Source
AI summary
Provided is a technology of conducting data transfer without 4-kB boundary crossing. A data transfer device includes a metadata creation section that creates metadata including a transfer destination address, a data transfer section that divides transfer data into a plurality of packets, imparts the metadata to a head packet, and sequentially transfers the plurality of packets, and a data transmission section that transmits the plurality of packets transferred by the data transfer section to the transfer destination address included in the metadata. The data transfer section imparts the metadata to the head packet of the plurality of packets, and transfers the head packet according to a write address that simulates a 4-kB boundary position.