The split-switching network (SSN): A high-performance multicast ATM switch

This paper proposes a new high-performance multicast ATM switch architecture. The switch, called the split-switching network (SSN), is based on banyan networks. The SSN achieves multicasting in a way that is non-typical for banyan-based switches: copying and routeing of multicast cells are carried out simultaneously and within the same fabric. Thus, cells are copied only when needed as they traverse the switch towards the appropriate output ports. The SSN consists of successive spliting stages, and buffering is provided in front of each stage. The SSN is non-blocking with complexity of order Nlog2/2N for a switch of size N, and is characterized by distributed and parallel control. The throughput-delay performance of the SSN is shown to be similar to that of a non-blocking output-buffering switch under different mixtures of unicast/multicast traffic. In particular, the SSN achieves a maximum throughput of 100 per cent and the cell delay and delay variation remain small for loads just below the maximum throughput.     

并发非阻塞自组织链表算法

利用自组织链表处理局部性较强的请求可提高性能,而非阻塞算法则能保证健壮性和可靠性。基于此,提出一种并发非阻塞自组织链表算法。使用MTF并发规则进行自组织操作,采用同步原语CAS实现并发程序,以保证查找、插入和删除操作的可线性化。实验结果表明,与Heller、Harris算法相比,随着读操作比例增大、链表变长,该算法的性能得到迅速改善。当读操作比例为90%、键值范围为4096时,其消耗时间最少。     

MPI技术在胶州湾水质预报系统的应用研究

为了能够更高效的提高胶州湾水质预报系统的运行速度,在原有基于串行模式的预报系统中引入了消息传递接口MPI (message-passing interface)并行处理技术,并在该系统中分别采用组通信模式和非阻塞通信模式,把整个水质预报系统分解为多个子任务,在基于MPI消息传递模式的集群系统中分别进行运算,通过实验表明了两种通信模式在运算速度上的差异,在预报系统中非阻塞通信模式比组通信模式更加优化.因此,非阻塞通信模式对水质预报模式的改进具有很大的潜力.     

T-NBC:透明的MPI非阻塞集合操作

在不修改应用程序的前提下,在MPI通信库中将阻塞的集合操作转化为非阻塞的实现可以将集合通信与紧跟在集合操作之后的计算重叠起来,从而提高应用的性能.在应用中,集合操作之后的计算包括集合通信无关的计算和集合通信相关的计算两类.集合通信可以与前者很好地重叠;由于后者需要访问通信数据,与后者的重叠和集合通信中多个集合子消息的通...     

A Mechanically Checked Proof of a Multiprocessor Result via a Uniprocessor View

We describe a mechanically checked correctness proof for a system of n processes, each running a simple, non-blocking counter algorithm. We prove that if the system runs longer than 5n steps, the counter is increased. The theorem is formalized in applicative Common Lisp and proved with the ACL2 theorem prover. The value of this paper lies not so much in the trivial algorithm addressed as in the method used to prove it correct. The method allows one to reason accurately about the behavior of a concurrent, multiprocess system by reasoning about the sequential computation carried out by a selected process, against a memory that is changed externally. Indeed, we prove general lemmas that allow shifting between the multiprocess and uniprocess views. We prove a safety property using a multiprocess view, project the property to a uniprocess view, and then prove a global progress property via a local, sequential computation argument. Our uniprocessor view is a formal compositional semantics for a shared memory system.     

改进型锁无关双端队列的设计与实现

高性能实时系统对系统性能、确定性和容错性有着更高的要求。非阻塞同步在任务同步方面满足要求,实现方法之一就是设计锁无关数据结构。介绍了设计锁无关数据结构算法的关键技术,通过对已有算法不足的分析提出了一种改进型的锁无关双端队列算法,介绍了对该算法的实验分析和实际应用。实验结果表明,该算法提高了访问双端队列的执行速度,并避免了多任务间同步引发的死锁、优先级逆转、低容错性等缺点。     

非周期演化数据流的无阻塞连接算法

数据流的连接常作为数据流查询操作的支撑算法.以往算法多考虑的是周期性演化的数据流,对于非周期性数据流连接涉及较少.提出一种变换高斯分布下的数据流连接算法.通过采样统计确定当前高斯中心点,并以此为中心划分数据块.提出在变换高斯分布下的确定数据连接块的方法.实验表明本算法与同类算法相比可以在有限的内存下产生更高的连接率,更小的I/O代价.     

On deadlock control for a class of generalised Petri net models of flexible manufacturing systems

This paper develops a deadlock prevention policy for a class of Petri nets that can model flexible manufacturing systems with assembly and disassembly operations. Siphons in a plant Petri net model are divided into elementary and dependent siphons according to the linear dependency of their characteristic T-vectors. The proposed approach is to make every siphon satisfy the controlled-siphon property (the cs-property), i.e., at any reachable marking, any siphon is max-marked, so that no deadlock states can be reached. The satisfiability of the cs-property is achieved by explicitly adding a monitor for each elementary siphon. The max-controllability of a dependent siphon is ensured by properly supervising its elementary siphons. More permissive behaviour of the non-blocking supervisor is obtained through the rearrangement of the output arcs of the monitors. Compared with existing policies reported in the literature, the advantage of the present method is that a small number of monitors are added and the iterative computing process is accordingly avoided. Finally, the application of the proposed method to an FMS example is presented.     

Java非阻塞I/O的应用

采用Java非阻塞I/O方式,一个线程可同时响应多个连接,能解决网络数据传输速度与PC机内数据交换速度不匹配.其客户端通过传递true(阻塞)或false(非阻塞)参数到configureBlocking(),改阻塞模式为非阻塞,客户端程序即可在单线程模式下无阻塞运行.服务器端通过建立服务器通道、设置阻塞模式、处理连接等实现.     

针对载荷/载荷舱监控的固定码率数据非阻塞模式实时解析与展示方法

临近空间探测科学实验是以浮空器、无人机等平台为手段, 获取多尺度、多层次、多类型的探测数据, 为临近空间认知体系构建提供支撑. 因为临近空间探测的复杂性和探测数据的多样性及重大的应用价值, 所以建立临近空间探测数据实时可视化展示, 有利于提升临近空间探测任务的安全、稳定开展. 由于传统的同步阻塞I/O处理模式在对数据流...