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With the growing popularity of task-based parallel programming, nowadays task-parallel programming libraries and languages are still with limited support for coordinating parallel tasks. Such limitation forces programmers to use additional independent components to coordinate the parallel tasks — the components can be third-party libraries or additional components in the same programming library or language. Moreover, mixing tasks and coordination components increase the difficulty of task-based programming, and blind schedulers for understanding tasks’ dependencies. In this paper, we propose a task-based parallel programming library, FunctionFlow, which coordinates tasks in the purpose of avoiding additional independent coordination components. First, we use dependency expression to represent ubiquitous tasks’ termination. The key idea behind dependency expression is to use && for both task’s termination and || for any task termination, along with the combination of dependency expressions. Second, as runtime support, we use a lightweight representation for dependency expression. Also, we use suspended-task queue to schedule tasks that still have prerequisites to run. Finally, we demonstrate FunctionFlow’s effectiveness in two aspects, case study about implementing popular parallel patterns with FunctionFlow, and performance comparision with state-of-the-art practice, TBB. Our demonstration shows that FunctionFlow can generally coordinate parallel tasks without involving additional components, along with comparable performance with TBB.

Data races are ubiquitous in multi-threaded applications, but they are by no means easy to detect. One of the most important reasons is the complexity of thread interleavings. A volume of research has been devoted to the interleaving-insensitive detection. However, all the previous work focuses on the uniform detection (unknown to the characteristics of thread interleavings), thereby making the detection defective in either reporting false positives or suffering from prohibitive overhead. To cope with the problem above, we propose an efficient, precise, and sound step-by-step resolution based on the characteristics of thread interleavings. We first try to tease apart the categories of thread interleavings from the several typical sources arising from the lock synchronizations. We then conduct a brief study and find a new and complex pattern the previous work cannot detect. It is also revealed that the simple pattern with the majority of thread interleavings can be resolved by a simple processing to achieve a big profit for the previous reordering-based design. Our final experimental results demonstrate the effectiveness of our empiricism-based approach, and show that 51.0% of execution time and 52.3% of trace size arising from the stateof-the-art reordering technique can be saved through a quick filtering of the simple pattern with a negligible (4.45%) performance overhead introduced on-the-fly.