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Unformatted text preview: Limits to Low-Latency Communication on High-Speed Networks CHANDRAMOHAN A. THEKKATH and HENRY M. LEVY University of Washington, Seattle The throughput of local area networks is rapidly increasing. For example, the bandwidth of new ATM networks and FDDI token rings is an order of magnitude greater than that of Ethernets. Other network technologies promise a bandwidth increase of yet another order of magnitude in a few years. However, in distributed systems, lowered latency rather than increased throughput is often of primary concern. This paper examines the system-level effects of newer high-speed network technologies on low-latency, cross-machine communications. To evaluate a number of influences, both hardware and software, we designed and imple- mented a new remote procedure call system targeted at providing low latency. We then ported this system to several hardware platforms (DECstation and SPARCstation) with several differ- ent networks and controllers (ATM, FDDI, and Ethernet). Comparing these systems allows us to explore the performance impact of alternative designs in the communication system with respect to achieving low latency, e.g., the network, the network controller, the host architecture and cache system, and the kernel and user-level runtime software. Our RPC system, which achieves substantially reduced call times (170 pseconds on an ATM network using DECstation 5000/200 hosts), allow us to isolate those components of next- generation networks and controllers that still stand in the way of low-latency communication. We demonstrate that new-generation processor technology and software design can reduce small-packet RPC times to near network-imposed limits, making network and controller design more crucial than ever to achieving truly low-latency communication. Categories and Subject Descriptors: B.4.2 [Input/ Output and Data Communications] In- put/Output Devices—channels and controllers; C.2.2 [Computer-Communication Networks]: Network Protocols—protocol architecture; C.2.4 [Computer-Communication Networks]: Dis- tributed Systems—distributed applications, network operating systems; D.4.4 [Operating Sys- tems]: Communications Management—message sending, network communication; D.4.7 [Oper- ating Systems]: Organization and Design—dwtributed systems General Terms: Design, Measurement, Performance Additional Key Words and Phrases: ATM networks, host-network interfaces, interprocess com- munication, remote procedure calls, transport level protocols This work was supported in part by the National Science Foundation under grants CCR-8619663, CCR-8703049, CCR-8907666, and CCR-9200832, by the Washington Technology Center, and by the Digital Equipment Corporation Systems Research Center and External Research Program, Hewlett-Packard Corp., and Apple Computer. C. Thekkath is supported in part by a fellowship from Intel Corp. H. Levy is supported in part by a Fullbright research award and by the INRIA....
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This note was uploaded on 10/06/2010 for the course CS 6210 taught by Professor Staff during the Fall '08 term at Georgia Tech.
- Fall '08