• Title/Summary/Keyword: context switching

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Development and Performance Study of a Zero-Copy File Transfer Mechanism for Ink-based PC Cluster Systems (VIA 기반 PC 클러스터 시스템을 위한 무복사 파일 전송 메커니즘의 개발 및 성능분석)

  • Park Sejin;Chung Sang-Hwa;Choi Bong-Sik;Kim Sang-Moon
    • Journal of KIISE:Computer Systems and Theory
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    • v.32 no.11_12
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    • pp.557-565
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    • 2005
  • This paper presents the development and implementation of a zero-copy file transfer mechanism that improves the efficiency of file transfers for PC cluster systems using hardware-based VIA(Virtual Interface Architecture) network adapters. VIA is one of the representative user-level communication interfaces, but because there is no library for file transfer, one copy occurs between kernel buffer and user boilers. Our mechanism presents a file transfer primitive that does not require the file system to be modified and allows the NIC to transfer data from the kernel buffer to the remote node directly without copying. To do this, we have developed a hardware-based VIA network adapter, which supports the PCI 64bit/66MHz bus and Gigabit Ethernet, as a NIC, and implemented a zero-copy file transfer mechanism. The experimental results show that the overhead of data coy and context switching in the sender is greatly reduced and the CPU utilization of the sender is reduced to $30\%\~40\%$ of the VIA send/receive mechanism. We demonstrate the performance of the zero-copy file transfer mechanism experimentally. and compare the results with those from existing file transfer mechanisms.

Design and Evaluation of a NIC-Driven Host-Independent Network System (네트워크 인터페이스 카드에 기반한 호스트 독립적인 네트워크 시스템의 설계 및 성능평가)

  • Yim Keun Soo;Cha Hojung;Koh Kern
    • Journal of KIISE:Computer Systems and Theory
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    • v.31 no.11
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    • pp.626-634
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    • 2004
  • In a client-server model, network server systems suffer from both heavy communication and computational loads. While communication channels become increasingly speedy, the existing protocol stack architectures still include mainly three performance bottlenecks of protocol stack processing, system call, and network interrupt overheads. To address these obstacles, in this paper we present a host-independent network system where a network interface card (NIC) is utilized in an efficient manner. First, by offloading network-related portion to the NIC, the host can fully utilize its processing power for other useful purposes. Second, it eliminates the system call overhead, such as context-switching and memory copy operations, since the host communicates with the NIC through its user-level libraries. Third, it a] so reduces the network interrupt operation count as the host handles the interrupt in a segment instead of a packet. The experimental results show that the proposed network system reduces the host CPU overhead for communication system by 68-71%. It also shows that the proposed system improves the communication speed by 11-83% under heavy computational and communication load conditions.