Early Credit Return for Buffer Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In credit-based flow control systems, particularly in chiplet systems, there is a delay in data transmission due to the conventional method where credits are returned only after data is read from the buffer, leading to halted packet sending and increased processing cycles, which affects system performance.
Innovation Solution
Implementing early credit return in credit-based flow control, where credits are returned before data is read from the buffer, allowing the sending device to continue sending packets without waiting for buffer processing, thereby reducing wait states and improving communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If credits are returned only after data is read from the buffer, then buffer processing is completed, but packet sending is halted and processing cycles increase
Solution Approach 1:
The receiving device performs preliminary action by returning credits before the data is fully read from the buffer. The buffer control unit determines when to return credits based on buffer entry alignment, allowing the sending device to continue transmitting packets without waiting for complete buffer processing, thus resolving the contradiction between ensuring buffer processing completion and maintaining packet sending continuity
2Productivity
If credits are returned early before data is read from the buffer, then packet sending continues without wait states, but buffer processing may not be complete
Solution Approach 1:
The buffer control unit implements feedback by continuously monitoring buffer entry alignment status and using this information to determine when to return credits. This feedback mechanism ensures that credits are returned at the appropriate moment when buffer entries are aligned, maintaining both packet sending continuity and buffer processing reliability
3Device complexity
If conventional credit return method is used, then buffer management is simple, but wait states increase and power consumption rises
Solution Approach 1:
The buffer control unit performs self-service by automatically monitoring buffer entry alignment and initiating credit returns without external intervention. This self-service mechanism eliminates the need for complex external buffer management while reducing wait states and lowering power consumption through early credit return
Data Source
AI summary
A device allocates buffer space for storing data received from another device. The other device has a credit balance corresponding to the amount of buffer space. A sending device reduces its number of credits by a cost of a packet and sends the packet. To ensure that the buffer does not overflow, the sending device spends a credit for each entry in the buffer that could be consumed by the sent data packet. When received data is added to the buffer without consuming a new entry, a response packet that returns a credit is sent to the sending device before the data is read from the buffer. Thus, the sending device is enabled to continue sending data without waiting for the buffer to be read, enabling the communication between the two devices to make more efficient use of the buffer.