  Modern radio telescopes like the Square Kilometer Array (SKA) will need to
process in real-time exabytes of radio-astronomical signals to construct a
high-resolution map of the sky. Near-Memory Computing (NMC) could alleviate the
performance bottlenecks due to frequent memory accesses in a state-of-the-art
radio-astronomy imaging algorithm. In this paper, we show that a sub-module
performing a two-dimensional fast Fourier transform (2D FFT) is memory bound
using CPI breakdown analysis on IBM Power9. Then, we present an NMC approach on
FPGA for 2D FFT that outperforms a CPU by up to a factor of 120x and performs
comparably to a high-end GPU, while using less bandwidth and memory.
