Monthly Archives: November 2015

Efficient Communication Using Ring Buffers – Early Results

Efficient Communication Using Ring Buffers – Early Results

  • Maxwell Walter, Jesper Puge Nielsen, and Sven Karlsson. Efficient Communication Using Ring Buffers — Early Results. In Proceedings of the Swedish Workshop on Multicore Computing (MCC 2015), Copenhagen, DK, 2015.
    [BibTeX] [Abstract]

    Communication is a vital concern to modern multiprocessor and multi-core systems, as communication between threads and processes on different cores can quickly become a performance bottle-neck. In addition, most communication mechanisms require synchronization protocols that are complicated to get right, further degrading performance. We propose a communication mechanism, based on shared memory, with built-in synchronization protocols. We model our communication structures, which we call ring buffers, around the communication mechanisms observed between current hardware and software systems. While our ring buffers are not operating system specific, we have designed our multi-core research operating system, FenixOS, around them. This makes communication a fundamental system component and allows us to provide efficient communication between threads, processes, the kernel, and device drivers. In this paper we describe our preliminary work on our ring buffer structures. We also provide early results comparing our ring buffers against several other common communication mechanisms, as well as a Linux ring buffer implementation.

    @InProceedings{2015-11-WALTER,
    title = {{Efficient Communication Using Ring Buffers -- Early Results}},
    author = {Maxwell Walter and Jesper Puge Nielsen and Sven Karlsson},
    booktitle = {{Proceedings of the Swedish Workshop on Multicore Computing (MCC 2015)}},
    address = {Copenhagen, DK},
    date = {2015-11-25/2015-11-26},
    year = {2015},
    abstract = {Communication is a vital concern to modern multiprocessor and multi-core systems, as communication between threads and processes on different cores can quickly become a performance bottle-neck. In addition, most communication mechanisms require synchronization protocols that are complicated to get right, further degrading performance. We propose a communication mechanism, based on shared memory, with built-in synchronization protocols. We model our communication structures, which we call ring buffers, around the communication mechanisms observed between current hardware and software systems.
    While our ring buffers are not operating system specific, we have designed our multi-core research operating system, FenixOS, around them. This makes communication a fundamental system component and allows us to provide efficient communication between threads, processes, the kernel, and device drivers. In this paper we describe our preliminary work on our ring buffer structures. We also provide early results comparing our ring buffers against several other common communication mechanisms, as well as a Linux ring buffer implementation.}
    }

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Designing a Lock-free Virtual Memory Management System

Designing a Lock-free Virtual Memory Management System

  • Jesper Puge Nielsen, Maxwell Walter, and Sven Karlsson. Designing a Lock-free Virtual Memory Management System. In Proceedings of the Swedish Workshop on Multicore Computing (MCC 2015), Copenhagen, DK, 2015.
    [BibTeX] [Abstract]

    Operating system developers must turn to new techniques to maintain scalability as the number of cores controlled by the operating system grows. Traditional lock based system design has proven to be easy to implement, but their performance fails to scale with the number of cores. In this paper we present the design of a virtual memory management system for a multi-core operating system. The system is designed without the use of locks. Instead, atomic operations are used to synchronize between threads. We discuss the challenges of designing a lock-free virtual memory management system, and present the solutions we have chosen. These includes a flat virtual address space design supporting lock-free concurrent modifications, and a new algorithm for sharing physical page frames between processes, without using locks to synchronize new physical page frame mappings and concurrent reclamation of physical page frames. We have implemented our design for the AMD64 architecture and evaluated it by comparing it to a lock based implementation.

    @InProceedings{2015-11-NIELSEN,
    title = {{Designing a Lock-free Virtual Memory Management System}},
    author = {Jesper Puge Nielsen and Maxwell Walter and Sven Karlsson},
    booktitle = {{Proceedings of the Swedish Workshop on Multicore Computing (MCC 2015)}},
    address = {Copenhagen, DK},
    date = {2015-11-25/2015-11-26},
    year = {2015},
    abstract = {Operating system developers must turn to new techniques to maintain scalability as the number of cores controlled by the operating system grows. Traditional lock based system design has proven to be easy to implement, but their performance fails to scale with the number of cores.
    In this paper we present the design of a virtual memory management system for a multi-core operating system. The system is designed without the use of locks. Instead, atomic operations are used to synchronize between threads. We discuss the challenges of designing a lock-free virtual memory management system, and present the solutions we have chosen. These includes a flat virtual address space design supporting lock-free concurrent modifications, and a new algorithm for sharing physical page frames between processes, without using locks to synchronize new physical page frame mappings and concurrent reclamation of physical page frames. We have implemented our design for the AMD64 architecture and evaluated it by comparing it to a lock based implementation.}
    }

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Smart Video Data

Smart Video Data

  • Andrea Cavallaro. Smart Video Data. Keynote lecture at European Data Forum, 2015.
    [BibTeX] [Abstract]

    Video capturing devices are ubiquitous. Cameras with microphones are increasingly worn by people, mounted on dashboards and micro-drones; installed in hallways, streets and stores. In this talk I will cover techniques that automatically extract actionable information from videos and camera networks to learn patterns of behaviour, to detect anomalies and to help predict intentions. I will focus on recent applications that are offering extraordinary opportunities to improve our businesses, safety and quality of life; discuss the associated scientific challenges and privacy implications.

    @Misc{2015-11-CAVALLARO,
    author = {Andrea Cavallaro},
    title = {{Smart Video Data}},
    howpublished = {Keynote lecture at European Data Forum},
    date = {2015-11-16},
    year = {2015},
    address = {Luxembourg},
    abstract = {Video capturing devices are ubiquitous. Cameras with microphones are increasingly worn by people, mounted on dashboards and micro-drones; installed in hallways, streets and stores. In this talk I will cover techniques that automatically extract actionable information from videos and camera networks to learn patterns of behaviour, to detect anomalies and to help predict intentions. I will focus on recent applications that are offering extraordinary opportunities to improve our businesses, safety and quality of life; discuss the associated scientific challenges and privacy implications.}
    }

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