Packet Transactions: High-level Programming for Line-Rate Switches

Many algorithms for congestion control, scheduling, network measurement, active queue management, security, and load balancing require custom processing of packets as they traverse the data plane of a network switch. To run at line rate, these data-plane algorithms must be in hardware. With today's switch hardware, algorithms cannot be changed, nor new algorithms installed, after a switch has been built. This paper shows how to program data-plane algorithms in a high-level language and compile those programs into low-level microcode that can run on emerging programmable line-rate switching chipsets. The key challenge is that these algorithms create and modify algorithmic state. The key idea to achieve line-rate programmability for stateful algorithms is the notion of a packet transaction : a sequential code block that is atomic and isolated from other such code blocks. We have developed this idea in Domino, a C-like imperative language to express data-plane algorithms. We show with many examples that Domino provides a convenient and natural way to express sophisticated data-plane algorithms, and show that these algorithms can be run at line rate with modest estimated die-area overhead.Comment: 16 page

Hillview:A trillion-cell spreadsheet for big data

Hillview is a distributed spreadsheet for browsing very large datasets that cannot be handled by a single machine. As a spreadsheet, Hillview provides a high degree of interactivity that permits data analysts to explore information quickly along many dimensions while switching visualizations on a whim. To provide the required responsiveness, Hillview introduces visualization sketches, or vizketches, as a simple idea to produce compact data visualizations. Vizketches combine algorithmic techniques for data summarization with computer graphics principles for efficient rendering. While simple, vizketches are effective at scaling the spreadsheet by parallelizing computation, reducing communication, providing progressive visualizations, and offering precise accuracy guarantees. Using Hillview running on eight servers, we can navigate and visualize datasets of tens of billions of rows and trillions of cells, much beyond the published capabilities of competing systems

Factors Influencing the Performance of a CPU-RFU Hybrid Architecture

Em face da acentuada revalorização da textualidade nas poéticas da década de 1960 em Portugal – perspectiva que, com algumas especificidades, também se verifica no contexto francês e espanhol –, a demarcação dos poetas emergentes na década seguinte é, por vezes, fortemente reactiva. Mas haverá uma diferença essencial entre estas duas inflexões, corporizadas em poéticas aparentemente distintas? E haverá algum momento, na segunda metade do século XX, em que efectivamente se concretize uma ruptura? No presente estudo, procura-se mostrar que, mais do que produzir uma ruptura, as poéticas emergentes nos anos sessenta do século XX consolidam uma tradição de modernidade escolhendo a sua vertente mais radical, enquanto as poéticas subsequentes preferem reatar a tradição mais remota da modernidade, em sentido baudelairiano. Apesar de estarmos perante dois diálogos diferentes com a tradição, é possível observar que, em ambos os casos, esta é retomada a um ponto que nos impede de falarmos de ruptura

Interacting with Large Distributed Datasets using Sketch

We present Sketch, a distributed software infrastructure for building interactive tools for exploring large datasets, distributed across multiple machines. We have built three sophisticated applications using this framework: a billion-row spreadsheet, a distributed log browser, and a distributed- systems performance debugging tool. Sketch applications allow interactive and responsive exploration of complex distributed datasets, scaling gracefully to large system sizes. The conflicting constraints of large-scale data and small timescales required by human interaction are difficult to satisfy simultaneously. Sketch exploits a sweet spot in this trade-off by exploiting the observation that the precision of a data view is limited by the resolution of the user?s screen. The system pushes data reduction operations to the data sources. The core Sketch abstraction provides a narrow programming interface; Sketch clients construct a distributed application by stacking modular components with identical interfaces, each providing a useful feature: network transparency, concurrency, fault-tolerance, straggler avoidance, round-trip reduction, distributed aggregation

1 Thesis Statement Spatial Computation — Summary of the Ph.D. Thesis —

Software compilation technology for targeting predicated architectures can be naturally adapted for performing the automatic synthesis of application-specific, custom hardware dataflow machines. This compilation methodology translates media processing kernels into hardware with a high degree of instructionlevel and pipeline parallelism. However, the resulting distributed computation structures are not as easily amenable as traditional monolithic superscalar processors at using acceleration mechanisms such as (correlated) prediction, speculation and register renaming. The lack of these mechanisms is a severe handicap when executing control-intensive code.