Bus Bridge Flush Control Circuit for Data Consistency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Data inconsistency issues arise in computer systems with bus bridges due to data buffering, leading to performance degradation when synchronization events occur and data remains posted in the bridge.
Innovation Solution
A flush request control circuit that records the buffer write pointer and compares it with the buffer read pointer to generate a flush acknowledgement signal, ensuring the buffering unit is empty before outputting the signal, thereby preventing false acknowledgments and allowing continuous data transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data buffering is used in the bridge to enhance performance through packetizing and pre-fetching data, then data transfer efficiency is improved, but data consistency cannot be guaranteed when synchronization events occur and data remains posted in the bridge
Solution Approach 1:
The bridge implements a feedback mechanism by monitoring the buffer status through read/write pointer comparison. When a flush request occurs, the bridge continuously checks whether the buffer is empty (read pointer equals write pointer) and provides feedback via a flush acknowledgment signal. This feedback loop ensures data consistency by confirming that all posted data has been transferred before allowing synchronization events to proceed, while maintaining high data transfer efficiency through continuous buffering operations.
2Reliability
If the bridge stops data transfer to ensure the buffering unit is empty during flush requests, then data consistency is maintained, but system performance degrades
Solution Approach 1:
The bridge maintains continuous data transfer operations even during flush requests by using pointer comparison to determine buffer status. Instead of stopping data transfer, the bridge continues posting data to the buffer while simultaneously checking whether the buffer is empty through pointer comparison. This allows the useful action of data transfer to continue uninterrupted while still ensuring data consistency through the flush acknowledgment mechanism that confirms buffer emptiness when needed.
3Device complexity
If the bridge uses simple buffer empty checking without pointer recording, then device complexity is reduced, but false flush acknowledgments may occur leading to data inconsistency
Solution Approach 1:
The bridge applies preliminary action by recording the write pointer value at the moment a flush request is received. This recorded pointer value serves as a reference point for subsequent buffer empty checking. By establishing this reference in advance, the bridge can accurately determine whether the buffer is truly empty by comparing the current read pointer against the recorded write pointer, preventing false flush acknowledgments while adding minimal complexity through a simple pointer recording mechanism.
Data Source
AI summary
A bridge capable of preventing data inconsistency is provided, in which a first master device outputs a flush request, a buffering unit buffers data or instructions, and a flush request control circuit records a buffer write pointer of the buffer according to the flush request and outputs a flush acknowledgement signal to the first master device in response of that a buffer read pointer of the buffering unit is identical to the recorded buffer write pointer.