With the rapid progress of high-performance cluster applications, data transfer between clusters in distant locations becomes more important. But, it is difficult to transfer data using parallel TCP streams on long distance high bandwidth network. In this paper, we microscopically observe parallel TCP streams on 10 Gbps network using our network analyzer, propose, implement, and evaluate "Stream Equalizer'' which relaxes self-congestion and balances throughput among streams.We evaluate it using a real wide-area network over the Pacific Ocean.The network analyzer and the Stream Equalizer are implemented on FPGA-based programmable high-speed network testbed TGNLE-1.

Proposes a scheme to realize a high-performance communication facility using a commodity network. This scheme does not require any special hardware or hardware-specific device drivers in order to adapt to many kinds of network interface cards (NICs). In this scheme, a reliable lightweight network protocol is handled directly on a data link layer called by a network device driver. An interrupt reaping technique is proposed to eliminate the hardware interrupt overhead when an application waits for a message. PM/Ethernet, an instance of the scheme, is implemented on Linux with minimal modification to the Linux kernel, and existing network device drivers are used without any modification. Using Pentium III 500-MHz PCs on Packet Engine's G-NIC II Gigabit Ethernet NIC, it achieves 77.5 MB/s bandwidth and 37.6 /spl mu/s round-trip time latency compared to that of TCP/IP, which achieves 46.7 MB/s bandwidth and 89.6 /spl mu/s round-trip time latency. The NAS parallel benchmark IS results show that MPI on PM/Ethernet achieves 75% better performance than MPI on TCP/IP and is 7.8% slower than that of MPI on Myrinet PM.

A high performance communication facility, called the GigaE PM, has been designed and implemented for parallel applications on clusters of computers using a Gigabit Ethernet. The GigaE PM provides not only a reliable high bandwidth and low latency communication function, but also supports existing network protocols such as TCP/IP. In the design of the GigaE PM, it is assumed that the Gigabit Ethernet card used has a dedicated processor and its program can be modied. A reliable communication mechanism for a parallel application is implemented on the rmware while existing network protocols are handled by an operating system kernel. A prototype system has been implemented using an Essential Communications Gigabit Ethernet card. The performance results show that a 48.3 s round trip time for a four byte user message, and 56.7 MBytes/sec bandwidth for a 1,468 byte message have been achieved on Intel Pentium II 400 MHz PCs. We have implemented MPICH-PM on top of the GigaE PM, and evaluat...

This paper designs an implementation of the MPI message passing interface using a zero copy message transfer primitive supported by a lower communication layer to realize a high performance communication library.The zero copy message transfer primitive requires a memory area pinned down to physical memory, which is a restricted quantity resource under a paging memory system.Allocation of pinned down memory by multiple simultaneous requests for sending and receiving without any control can cause deadlock.To avoid this deadlock, we have introduced: i) separate of control of send/receive pin-down memory areas to ensure that at least one send and receive may be processed concurrently, and ii) delayed queues to handle the postponed message passing operations which could not be pinned-down.

A new and more highly efficient gang scheduling implementation technique is the basis for this paper. Network preemption, in which network interface contexts are saved and restored, has already been proposed to enable parallel applications to perform efficent user-level communication. This network preemption technique can be used to for detecting global state, such as deadlock, of a parallel program execution. A gang scheduler, SCore-D, using the network preemption technique is implemented with PM, a user-level communication library. This paper evaluates network preemption gang scheduling overhead using eight NAS parallel benchmark programs. The results of this evaluation illustrate that the saving and restoring network contexts occupies almost half of the total gang scheduling overhead. A new mechanism, having multiple network contexts and merely switching the context pointers without saving and restoring the network contexts, is proposed. The NAS parallel benchmark evaluation shows that gang scheduling overhead is almost halved. The maximum gang scheduling overhead among benchmark programs is less than 10%, with a 40msec time slice on 64 single-way PentiumPros, connected by Myrinet to form a PC cluster. The numbers of secondary cache misses are counted, and it is found that network preemption with multiple network contexts is more cache-effective than a single network context. The observed scheduling overhead for applications running on 64 nodes can only be a small percent of the execution time. The gang scheduling overheads of switching two NAS parallel benchmark programs are also evaluated. The additional overheads are less than 2% in most cases, with a 100msec time slice on 64 nodes. This slightly higher scheduling overheads than for switching a single parallel process comes from more frequent cache misses. This paper contributes the following findings; i) gang scheduling overhead with network preemption can be sufficiently low, ii) proposed network preemption with multiple network contexts is more cache-effective than a single network context, and, iii) network preemption can be applied to detect global states of user parallel processes. SCore-D gang scheduler realized by network preemption can utilize processor resources by the detecting the global state of user parallel processes. Network preemption with multiple contexts exhibits highly efficient gang scheduling. The combination of low scheduling overhead and the global state detection mechanism achieves an interactive parallel programming where parallel program development and the production run of parallel programs can be mixed freely.

A gigabit-to-the-home (GTTH) system is proposed as a future ultra-broadband access network and its feasibility is investigated. GTTH is based on PON architecture and offers a very large downstream capacity of 2.5 Gb/s. Thus, various broadband communication services and digital video broadcasting services with a great many channels can be simultaneously provided. GTTH also has high flexibility due to its multiple-interface architecture, which enables multiple systems to be integrated regardless of their signal formats, protocols and transfer modes. In order to reduce the cost of GTTH-ONU, a high-speed CMOS DMUX IC, a waveguide PIN-PD and a one-chip receiver are developed. The service integration capability of GTTH is shown through a GTTH demonstration system.

A QOS control is one of the most important factors in continuous media applications. The QOS levels of the applications should be maintained even if several continuous media applications are running concurrently. Also, the QOS levels should be changed according to a number of applications and their respective importances when a system is overloaded. This paper presents our experience with a video-on-demand system that supports a dynamic QOS control scheme on Real-Time Mach, and shows the necessity of a real-time resource management for building such applications.