The Impact of Cache and Dynamic Memory Management in Static Dataflow Applications

Dataflow is a parallel and generic model of computation that is agnostic of the underlying multi/many-core architecture executing it. State-of-the-art frameworks allow fast development of dataflow applications providing memory, communicating, and computing optimizations by design time exploration. However, the frameworks usually do not consider cache memory behavior when generating code. A generally accepted idea is that bigger and multi-level caches improve the performance of applications. This work evaluates such a hypothesis in a broad experiment campaign adopting different multi-core configurations related to the number of cores and cache parameters (size, sharing, controllers). The results show that bigger is not always better, and the foreseen future of more cores and bigger caches do not guarantee software-free better performance for dataflow applications. Additionally, this work investigates the adoption of two memory management strategies for dataflow applications: Copy-on-Write (CoW) and Non-Temporal Memory transfers (NTM). Experimental results addressing state-of-the-art applications show that NTM and CoW can contribute to reduce the execution time to -5.3% and - 15.8 % , respectively. CoW, specifically, shows improvements up to -21.8% in energy consumption with -16.8% of average among 22 different cache configurations.