To improve the scalability, several many-core architectures use message passing instead of shared memory accesses for communication. Unfortunately, Direct Memory Access (DMA) transfers in a shared address space are usually used to emulate message passing, which entails a lot of overhead and thwarts the advantages of message passing. Recently proposed register-level message passing alternatives use special instructions to send the contents of a single register to another core. The reduced communication overhead and architectural simplicity lead to good many-core scalability. After investigating several other approaches in terms of hardware complexity and throughput overhead, we recommend a small instruction set extension to enable register-level message passing at minimal hardware costs and describe its integration into a classical five stage RISC-V pipeline.

中文翻译：

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PIMP My Many-Core：管道集成消息传递

为了提高可扩展性，一些众核架构使用消息传递而不是共享内存访问进行通信。不幸的是，共享地址空间中的直接内存访问 (DMA) 传输通常用于模拟消息传递，这需要大量开销并阻碍消息传递的优势。最近提出的寄存器级消息传递替代方案使用特殊指令将单个寄存器的内容发送到另一个内核。减少的通信开销和架构的简单性带来了良好的众核可扩展性。在研究了硬件复杂性和吞吐量开销方面的其他几种方法之后，