PPoPP 2019
Sat 16 - Wed 20 February 2019 Washington, DC, United States

We present the multi-dimensional elasticity support in IBM Streams 4.3. Automatic operator fusion and dynamic threading were introduced in IBM Streams 4.2, which made it easier to map distributed stream processing to multicore systems through a low-cost operator scheduler and thread count elasticity. To enable these features, the same threading model was applied to the entire application. However, in practice, we have found that some applications have regions best executed under different threading models. In this poster, we introduce threading model elasticity and design a coherent ecosystem for both threading model elasticity and thread count elasticity. We propose an online, stable multi-dimensional elastic control algorithm that adapts different regions of a streaming application to different threading models and number of threads.