Tracing the MPI-IO Calls' Disk Accesses
With parallel file I/O we are faced with the situation that we do not have appropriate tools to get an insight into the I/O server behavior depending on the I/O calls in the corresponding parallel MPI program. We present an approach that allows us to also get event traces from the I/O server environment and to merge them with the client trace. Corresponding events will be matched and visualized. We integrate this functionality into the parallel file system PVFS2 and the MPICH2 tool Jumpshot.

title: Bottleneck Detection in Parallel File Systems with Trace-Based Performance Monitoring
abstract: Today we recognize a high demand for powerful storage. In industry this issue is tackled either with large storage area networks, or by deploying parallel file systems on top of RAID systems or on smaller storage networks. The bigger the system gets the more important is the ability to analyze the performance and to identify bottlenecks in the architecture and the applications. 
 
We extended the performance monitor available in the parallel file system PVFS2 by including statistics of the server process and information of the system. Performance monitor data is available during runtime and the server process was modified to store this data in off-line traces suitable for post-mortem analysis. These values can be used to detect bottlenecks in the system. Some measured results demonstrate how these help to identify bottlenecks and may assists to rank the servers depending on their capabilities.

title: Load Management on Multiprocessor Systems
abstract: 1 I n t r o d u c t i o n During the last years much research has been devoted to the development of multiprocessor systems. There are not only considerable advances in hardware architecture but also in the design and implementa t ion of software tools. Nevertheless, it is still easier to build a parallel machine than to use it efficiently. Two ma jo r types of parallel computers are available now: multiprocessor systems with shared memory and systems with distributed memory. Most of the problems concerning programming and running programs efficiently do not exist for shared memory systems due to the fact tha t these machines resemble monoprocessor systems with mult i tasking facilities. This paper completely concentrates on multiprocessors with distributed memory. Using systems with distributed memory usually makes program development and performance tuning of the programs very difficult. One severe problem is the load imbalance between processing nodes tha t may appear during runtime. Two approaches can be used to cope with this particular type of problem which can sometimes reduce the performance of a parallel system to that of a single monoprocessor: A static approach manages the distribution of processes to the processors before runt ime (usually called mapping) . In many cases this approach requires a priori knowledge about the behaviour of the program, i.e. execution t imes of the processes or precedence relations between them. If this a priori knowledge is not available, a dynamic approach is applied, where the distribution of processes happens during runtime of the program. This approach is referred to as load sharing or load balancing.

title: An Open Monitoring System for Parallel and Distributed Programs
abstract: The on-line monitoring interface specification OMIS provides means for developing more powerful tool environments for parallel and distributed systems. It specifies the interaction between any tool and a monitoring system which is responsible for observing and manipulating the programs' execution. By having this well defined interface it is now possible to concurrently use several tools of possibly different developers with the same program run. The research group at LRR-TUM currently designs an OMIS compliant monitoring system for PVM running on workstation clusters. Tool developers can use this implementation to attach their own on-line tools to the system.

title: Efficiently building on-line tools for distributed heterogeneous environments
abstract: Software development is getting more and more complex, especially within distributed middleware-based environments. A major drawback during the overall software development process is the lack of on-line tools, i.e. tools applied as soon as there is a running prototype of an application. The MIMO MIddleware MOnitor provides a solution to this problem by implementing a framework for an efficient development of on-line tools. 
 
This paper presents a methodology for developing on-line tools with MIMO. As an example scenario, we choose a distributed medical image reconstruction application, which represents a test case with high performance requirements. Our distributed, CORBA-based application is instrumented for being observed with MIMO and related tools. Additionally, load balancing mechanisms are integrated for further performance improvements. 
 
As a result, we obtain an integrated tool environment for observing and steering the image reconstruction application. By using our rapid tool development process, the integration of on-line tools shows to be very convenient and enables an efficient tool deployment.

title: Performance Assessment of Parallel Spectral Analysis: Towards a Practical Performance Model for Parallel Medical Applications
abstract: To determine the need for a parallel computer on campus a committee of the Graduate Program in Computer Science surveyed selected Dartmouth College faculty and students in December and January We hope that the information in this report can be used by many groups on campus including the Computer Science graduate program and DAGS summer institute Kiewit s NH Supercomputer Initiative and by numerous researchers hoping to collaborate with people in other disciplines We found signi cant interest in parallel supercomputing on campus An on campus par allel supercomputing facility would not only support numerous courses and research projects but would provide a locus for intellectual activity in parallel computing encouraging interdisci plinary collaboration We believe that this report is a rst step in that direction All of the committee members can be reached by email at fullname Dartmouth edu where dots replace spaces in the name e g David Kotz Dartmouth edu Dartmouth Parallel Computer Needs January

title: Standard-cell-based design methodology for high-performance support chips
abstract: We describe the methodology used for the design of a set of CMOS support chips used in the IBM S/390® Parallel Enterprise Server Generations 3 and 4. The logic design is based on functional units, and the majority of the logic is implemented by standard cell elements placed and routed flat, using timing-driven techniques. Custom library elements are used wherever needed for performance reasons. Using this approach, a density has been achieved that is comparable to those of contemporary custom designs, combined with very attractive turnaround times.

title: Power-delay product minimization in high-performance 64-bit carry-select adders
abstract: This paper analyzes methods to minimize the power-delay product of 64-bit carry-select adders intended for high-performance and low-power applications. A first realization in 0.18-/spl mu/m partially depleted (PD) silicon-on-insulator (SOI), using complex branch-based logic (BBL) cells, results in a delay of 720 ps and a power dissipation of 96 mW at 1.5 V. The reduction of the stack height in the critical path, combined with the optimization of the global carry network with cell sharing and the selection of 8-bit pre-sums, leads to a reduction of the power-delay product by 75%. The automatic tuning of the transistor widths in 0.13-/spl mu/m PD SOI produces an energy-efficient 64-bit adder which has a delay of 326 ps and a power dissipation of 23 mW only at 1.1 V.

title: Analyzing Metadata Performance in Distributed File Systems
abstract: The performance of metadata processing in large distributed file systems currently presents larger challenges than scaling of data throughput. The paper presents a novel, distributed benchmark called DMetabench for measuring the performance of metadata operations (e.g. file creation). DMetabench runs in environments with potentially thousands of nodes and allows an assessment of the scalability of metadata operations. Additionally, precise run-time performance data is preserved which allows for a better understanding of performance artifacts. Validation results from production file systems at the Leibniz Supercomputing Centre (LRZ) are provided and discussed. Possible applications of knowledge about metadata performance scaling include the choice of an optimal parallelization strategy for metadata-itensive workload in a specific runtime environment.