Abstract
Effective task scheduling in stream computing systems can reduce the latency by minimizing inter-node communication. However, this approach often requires restarting tasks to change their deployment locations, resulting in significant system overhead and making it inadequate especially in dynamically changing data stream environments. To address this issue, we propose Ns-Stream, a hierarchical data scheduler that dynamically adjusts data distribution weights between near-source and off-source tasks. Our solution includes: (1) We observe that communication overhead from off-source data processing significantly impacts system latency when tasks' resources are ample. However, as the resources become limited, the computational power required by tasks becomes the key constraint on system performance. (2) During initialization scheduling, we deploy tasks with potential communication to the same node using the graph convolutional network, thus avoiding the need for runtime task scheduling. (3) We dynamically adjust data distribution weights between near-source and off-source tasks based on their computing capabilities, prioritizing local processing of data tuples (within the same worker and node) to optimize resource utilization and reduce data transmission overhead. (4) Experimental results demonstrate significant improvements made by Ns-Stream: reducing maximum system latency by 40% and increasing maximum throughput by 55% compared to existing state-of-the-art works.
Funding Information
  • National Natural Science Foundation of China (62372419)
  • Fundamental Research Funds for the Central Universities (265QZ2021001)

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