Ineffective concurrency mechanisms in an operating system can lead to low performance in both single and multiprocessor environments. Practical setbacks involved with attempting overly invasive kernel changes have made it difficult in the past to implement new and innovative concurrency systems. This paper describes the rationale behind interfaces in the DragonFly BSD operating system intended to provide high performance and scalability on multiprocessor architectures. Using a lock-free processor centric approach, DragonFly BSD has developed a unique thread system with the potential for excellent scalability.

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