LerGAN: A Zero-Free, Low Data Movement and PIM-Based GAN Architecture

As a powerful unsupervised learning method, Generative Adversarial Network (GAN) plays an important role in many domains such as video prediction and autonomous driving. It is one of the ten breakthrough technologies in 2018 reported in MIT Technology Review. However, training a GAN imposes three more challenges: (1) intensive communication caused by complex train phases of GAN, (2) much more ineffectual computations caused by special convolutions, and (3) more frequent off-chip memory accesses for exchanging inter-mediate data between the generator and the discriminator. In this paper, we propose LerGAN, a PIM-based GAN accelerator to address the challenges of training GAN. We first propose a zero-free data reshaping scheme for ReRAM-based PIM, which removes the zero-related computations. We then propose a 3D-connected PIM, which can reconfigure connections inside PIM dynamically according to dataflows of propagation and updating. Our proposed techniques reduce data movement to a great extent, avoiding I/O to become a bottleneck of training GANs. Finally, we propose LerGAN based on these two techniques, providing different levels of accelerating GAN for programmers. Experiments shows that LerGAN achieves 47.2X, 21.42X and 7.46X speedup over FPGA-based GAN accelerator, GPU platform, and ReRAM-based neural network accelerator respectively. Moreover, LerGAN achieves 9.75X, 7.68X energy saving on average over GPU platform, ReRAM-based neural network accelerator respectively, and has 1.04X energy consuming over FPGA-based GAN accelerator.