User-process communication performance in networks of computers

Cabrera, Luis-Felipe; Hunter, Edward; Karels, Michael J.; Hosher, D.A.

doi:10.1109/32.4621

Cited by 63 publications

(10 citation statements)

References 12 publications

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“…The bimodal operation of the mbuf allocation algorithm causes the hump between 1 byte and 1024 bytes and part of the hump between 4 kilobytes and 5 kilobytes, largely because of the resulting numbers of calls to the mbuf allocation routine. Others have also remarked on this bimodality [4,13].…”

Section: Effects Of Message Size On Processing Time Breakdownsmentioning

confidence: 88%

Profiling and reducing processing overheads in TCP/IP

Kay

Pasquale

1996

IEEE/ACM Trans. Networking

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This paper presents detailed measurements of processing overheads for the Ultrix 4.2a implementation of TCP/IP network software running on a DECstation 5000/200. The performance results were used to unco ver throughput and latency bottlenecks. We present a scheme for impro ving throughput when sending large messages by a voiding most checksum computations in a relatively safe manner. We also show that for the implementation we studied, reducing latency (when sending small messages) is a more dif ficult problem because processing overheads are spread over many operations; gaining a significant savings would require the optimization of many different mechanisms. This is especially important because, when processing a realistic w orkload, we ha ve found that non-data-touching operations consume more time in aggre gate than data-touching operations. IntroductionWe analyze TCP/IP [30] and UDP/IP [29] processing overheads given a real w orkload on a DECstation 5000/200 running Ultrix 4.2a, and we use this information to guide our development of new optimizations. The cost of various processing overheads depend on message size; consequently, our optimizations take into account the message size distributions derived from the network traffic in our environment (which is not atypical of many academic and office environments).In our analysis of the TCP/IP and UDP/IP LAN and WAN traffic we were able to collect, we fi nd that message sizes are f ar from uniformly distributed; rather, most messages are either very small or very large. Small messages are usually used to carry control information, whereas lar ge messages typically carry bulk data. Different kinds of optimizations can improve processing speed for each type of traffic; in this paper we discuss both.Typical processing time breakdowns for short (i.e. 64-128 byte) control messages fundamentally differ from those of long multiple kilobyte data messages. The processing time of large messages is dominated by data-touching operations such as cop ying and computing checksums [4, 8-11, 15, 24, 36] because these operations must be applied to each byte. However, small messages have few bytes of data, and thus their processing time is dominated by non-data-touching operations.To optimize processing of large messages, we describe a checksum redundancy a voidance algorithm that eliminates most checksum processing without sacrificing reliability. Since checksum processing alone consumes nearly half the total processing time (of large messages), this optimization improves throughput considerably.On both the LAN and WAN we studied, both of which are typical Unix-networking environments, small messages far outnumber large messages. In fact, even though processing a large message requires more time, the large proportion of small messages causes the cumulative non-data-touching processing time to exceed the cumulative data-touching processing time. We show that it w ould be difficult to significantly reduce the a verage processing time of non-datatouching overheads, at lea...

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Section: Effects Of Message Size On Processing Time Breakdownsmentioning

confidence: 88%

Profiling and reducing processing overheads in TCP/IP

Kay

Pasquale

1996

IEEE/ACM Trans. Networking

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“…In particular, it is not clear if the loaded medium directly impacts the transport functions or if it affects the data link layer only. In [2] an experimental analysis is presented where also the case of a loaded communication medium is taken into account. The resuIts reported qualitatively suggest that loading conditions exert a strong influence on throughput behavior, but the background load conditions are not reported in a quantitative manner.…”

Section: Introductionmentioning

confidence: 99%

TCP/IP measured performance over an ethernet local network

Braccini

Bimbo

Vicario

et al. 1992

Trans Emerging Tel Tech

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Both a reliable transfer and a datagram transmission protocol are provided at the transport level of the Internet protocol suite. In this paper, an evaluation of the performance of these different protocols in the presence of background load is presented. The experimental analysis was carried out on an Ethernet Local Area Network with PC‐type workstations. The loading conditions were established by means of an artificial traffic generator. A reproducible experimental environment and a methodology to achieve accuracy in measurements were developed.

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“…The figures give only an idea on the possible performance of XTP when implemented in the user level. Other detailed performance tests can be found in [Cab88] and [Nic91] for TCP and in [Fan93] for XTP. A user level implementation of protocol of TCP is described in [The93].…”

Section: Performance Testsmentioning

confidence: 99%

High performance presentation and transport mechanisms for integrated communication subsystems

Dabbous

1995

IFIP Advances in Information and Communication Technology

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The performance enhancement of communication protocols is an essential step toward the building of high performance communication subsystems. Integrated Layer Processing (ILP) has been proposed as an engineering principle for the optimization of communication protocol implementations. However, the applicability of this principle to complete operational communication subsystems has not been yet addressed. This is in part due to the lack of high performance implementation of presentation and transport functions. In this paper, we show to what extent "ILP based" optimizations improve the performance of some data manipulation functions (e.g. presentation encoding or checksumming) independently. We present how some of these implementation optimization techniques were applied to the ASN.l encodings rules. We also analyze the impact of such optimization techniques according to the support hardware. A prototype implementation of the XTP protocol is also described. ILP based optimization applied to the checksum calculation algorithm show that an important performance enhancement can be achieved. These results should facilitate the support of ILP within an operational communication subsystem.

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User-process communication performance in networks of computers

Cited by 63 publications

References 12 publications

Profiling and reducing processing overheads in TCP/IP

Profiling and reducing processing overheads in TCP/IP

TCP/IP measured performance over an ethernet local network

High performance presentation and transport mechanisms for integrated communication subsystems

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