High Performance Messaging on Workstations: Illinois Fast Messages (FM) for Myrinet
High Performance Messaging on Workstations: Illinois Fast Messages (FM) for Myrinet
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DOI：
10.1109/superc.1995.32
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发表时间：
1995-12
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影响因子：
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通讯作者：
S. Pakin;Mario Lauria;A. Chien
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作者：
S. Pakin;Mario Lauria;A. Chien
在大多数计算机系统中，软件开销主导了消息传递的成本，降低了传递的性能，特别是对于短消息。需要高效的软件消息传递层来将硬件性能传递到应用程序级别，并支持紧密耦合的工作站集群。Illinois Fast Messages（FM）1.0是一个高速消息传递层，可为短消息提供低延迟和高带宽。对于128字节的数据包，FM在Myrinet连接的SPARC站（用户级到用户级）上实现了16.2MB/s的带宽和32 µs的单向延迟。对于较短的数据包，我们测得的单向延迟为25 µs，对于较大的数据包，带宽高达19.6MB/s -传输带宽大于OC-3。FM也比Myrinet API消息传递层更上级，不仅在延迟和可用带宽方面，而且在消息半功率点（n_{\frac{1}{2}}）方面，它小两个数量级（54对4，409字节）。我们描述了FM消息原语和关键的设计问题，在建立一个低延迟的消息层的工作站集群。有几个问题至关重要：主机和网络协处理器之间的劳动分工、输入/输出（I/O）总线的管理以及缓冲器管理。为了实现高性能，消息传递层应该为主机分配尽可能多的功能。如果网络接口具有DMA功能，则应不对称地使用I/O总线，主机处理器将数据移动到网络，并利用DMA将数据移动到主机。最后，网络协处理器中的缓冲区管理应该非常简单，并匹配网络协处理器和主机存储器之间的队列结构。详细的测量显示了这些功能中的每一个如何有助于高性能。
In most computer systems, software overhead dominates the cost of messaging, reducing delivered performance, especially for short messages. Efficient software messaging layers are needed to deliver the hardware performance to the application level and to support tightly-coupled workstation clusters. Illinois Fast Messages (FM) 1.0 is a high speed messaging layer that delivers low latency and high bandwidth for short messages. For 128-byte packets, FM achieves bandwidths of 16.2MB/s and one-way latencies 32 µs on Myrinet-connected SPARCstations (user-level to user-level). For shorter packets, we have measured one-way latencies of 25 µs, and for larger packets, bandwidth as high as to 19.6MB/s — delivered bandwidth greater than OC-3. FM is also superior to the Myrinet API messaging layer, not just in terms of latency and usable bandwidth, but also in terms of the message half-power point (n_{\frac{1}{2}}), which is two orders of magnitude smaller (54 vs. 4,409 bytes). We describe the FM messaging primitives and the critical design issues in building a low-latency messaging layers for workstation clusters. Several issues are critical: the division of labor between host and network coprocessor, management of the input/output (I/O) bus, and buffer management. To achieve high performance, messaging layers should assign as much functionality as possible to the host. If the network interface has DMA capability, the I/Obus should be used asymmetrically, with the host processor moving data to the network and exploiting DMA to move data to the host. Finally, buffer management should be extremely simple in the network coprocessor and match queue structures between the network coprocessor and host memory. Detailed measurements show how each of these features contribute to high performance.