Efficient Support of AXI4 Transaction Ordering Requirements in Many-Core Architecture

The Advanced Microcontroller Bus Architecture (AMBA) Advanced eXtensible Interface 4 (AXI4) protocol was initially a bus oriented interface designed for on-chip communication. To offer the possibility of utilizing the AXI4 based processors and peripherals in the on-chip network based system, we propose a whole system architecture solution to make the AXI4 protocol compatible with the Network-on-Chip (NoC) based communication interconnect in the many-core architecture. Due to the out-of-order transaction in the NoC interconnect, which conflicts with the ordering requirements specified by the AXI4 protocol, we especially focus on the design of the transaction ordering units, realizing a high-performance and low cost (area) solution to the ordering requirements by the sequence ID (seq_ID) reuse mechanism and a simple but smart seq_ID synchronization process. Besides, the micro-architectures and the functionalities of the transaction ordering units are described and explained in detail for ease of implementation. The experimental results in a C++ based system simulator show that, compared with the state-of-the-art works, our solution can maximally increase the system throughput by 66.0% and decrease the transaction queueing delay in the master-side ordering unit by 91.2%.