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The Liberty Research Group

FastForward for Concurrent Threaded Pipelines [abstract] (PDF)
John Giacomoni, Tipp Moseley, and Manish Vachharajani
University of Colorado Technical Report CU-CS-1023-07, January 2007.

The performance, cost, and flexibility of commodity multi-core systems make them appealing for threaded applications. Unfortunately, popular threading techniques require independent code regions, use expensive synchronization primitives, and use expensive communication mechanisms. Recently, researchers have proposed several Concurrent Threaded Pipeline architectures (CTP) which relax the data independence requirement and can increase computational throughput proportionately to the pipeline depth. Examples include Decoupled Software Pipelining, which focuses on compiler based extraction of pipelines from sequential codes, and the Frame Shared Memory architecture, which focuses specifically on network processing. CTP architectures show great promise for threading applications given a low-overhead high-speed blocking queue implementation.

This paper presents the FastForward system, a novel software-only low-overhead high-speed blocking queue implementation for CTPs. FastForward uses a novel domain-specific adaptation of concurrent lock-free queues (CLF) in conjunction with a clever memory organization to provide the fast, low-overhead, queue operations. The key to FastForward's success is its domain specific optimization based on careful tuning for modern multi-core microarchitectures. Enqueue and dequeue times are as low as 35 ns, 5 times faster than the next best solution.