RDMA Capable iWARP over Datagrams
RDMA Capable iWARP over Datagrams
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支持 RDMA 的 iWARP 数据报
DOI：
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发表时间：
2011
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通讯作者：
P. Balaji
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文献类型：
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作者：
Ryan E. Grant;Mohammad J. Rashti;A. Afsahi;P. Balaji
iWARP是一种最先进的基于高速连接的RDMA网络技术，用于以太网网络，在以太网上提供类似infiniband的零复制和单侧通信能力。尽管iWARP提供了很多好处，但许多数据中心和基于web的应用程序，如股票市场交易和流媒体应用程序，依赖于基于数据gram的语义（主要是通过UDP/IP），无法利用它，因为iWARP标准只定义在可靠的、面向连接的传输上。本文提出了一种适用于可靠和不可靠数据的RDMA模型。使用数据图的能力大大扩展了iWARP服务的应用程序空间，并为iWARP带来了无连接传输的可扩展性优势。在我们之前的工作中，我们开发了一个使用发送/接收语义的iWARP数据图解决方案，与当前基于tcp的iWARP相比，它具有出色的内存可伸缩性和性能优势。在本文中，我们展示了一种改进的iWARP设计，它在数据图上提供了真正的RDMA语义。具体来说，由于传统的RDMA语义不能很好地映射到不可靠的通信，我们提出了RDMA Write- record，这是第一个也是唯一一个能够在不可靠和可靠数据克上支持RDMA Write的方法。我们通过一个概念验证软件实现来证明data gram-iWARP在实际应用中是可行的。我们提出的RDMA Write-Record方法在设计时考虑了数据丢失问题，可以在丢包的情况下提供优越的性能。通过微基准测试表明，与传统的iWARP相比，使用支持RDMA的数据克-iWARP可以实现大消息带宽最多增加256%，小消息延迟最多改善24.4%。对于应用程序的结果，我们将重点放在流应用程序上，显示内存使用提高了24%，性能提高了74%，尽管所提出的方法也适用于高性能计算领域。
iWARP is a state of the art high-speed connection-based RDMA networking technology for Ethernet networks to provide InfiniBand-like zero-copy and one-sided communication capabilities over Ethernet. Despite the benefits offered by iWARP, many data center and web-based applications, such as stock-market trading and media-streaming applications, that rely on data gram-based semantics (mostly through UDP/IP) cannot take advantage of it because the iWARP standard is only defined over reliable, connection-oriented transports. This paper presents an RDMA model that functions over reliable and unreliable data grams. The ability to use data grams significantly expands the application space serviced by iWARP and can bring the scalability advantages of a connectionless transport to iWARP. In our previous work, we had developed an iWARP data gram solution using send/receive semantics showing excellent memory scalability and performance benefits over the current TCP-based iWARP. In this paper, we demonstrate an improved iWARP design that provides true RDMA semantics over data grams. Specifically, because traditional RDMA semantics do not map well to unreliable communication, we propose RDMA Write-Record, the first and the only method capable of supporting RDMA Write over both unreliable and reliable data grams. We demonstrate through a proof-of-concept software implementation that data gram-iWARP is feasible for real-world applications. Our proposed RDMA Write-Record method has been designed with data loss in mind and can provide superior performance under conditions of packet loss. It is shown through micro-benchmarks that by using RDMA capable data gram-iWARP a maximum of 256% increase in large message bandwidth and a maximum of 24.4\% improvement in small message latency can be achieved over traditional iWARP. For application results we focus on streaming applications, showing a 24% improvement in memory usage and up to a 74% improvement in performance, although the proposed approach is also applicable to the HPC domain.