Active-Routing: Compute on the Way for Near-Data Processing

The explosion of data availability and the demand for faster data analysis have led to the emergence of applications exhibiting large memory footprint and low data reuse rate. These workloads, ranging from neural networks to graph processing, expose compute kernels that operate over myriads of data. Significant data movement requirements of these kernels impose heavy stress on modern memory subsystems and communication fabrics. To mitigate the worsening gap between high CPU computation density and deficient memory bandwidth, solutions like memory networks and near-data processing designs are being architected to improve system performance substantially. In this work, we examine the idea of mapping compute kernels to the memory network so as to leverage in-network computing in data-flow style, by means of near-data processing. We propose Active-Routing, an in-network compute architecture that enables computation on the way for near-data processing by exploiting patterns of aggregation over intermediate results of arithmetic operators. The proposed architecture leverages the massive memory-level parallelism and network concurrency to optimize the aggregation operations along a dynamically built Active-Routing Tree. Our evaluations show that Active-Routing can achieve upto 7x speedup with an average of 60% performance improvement, and reduce the energy-delay product by 80% across various benchmarks compared to the state-of-the-art processing-in-memory architecture.