Loom: Exploiting Weight and Activation Precisions to Accelerate Convolutional Neural Networks

Loom (LM), a hardware inference accelerator for Convolutional Neural Networks (CNNs) is presented. In LM every bit of data precision that can be saved translates to proportional performance gains. For both weights and activations LM exploits profile-derived per layer precisions. However, at runtime LM further trims activation precisions at a much smaller than a layer granularity. On average, across several image classification CNNs and for a configuration that can perform the equivalent of 128 16b × 16b multiply-accumulate operations per cycle LM outperforms a state-of-the-art bit-parallel accelerator [3] by 3.19 × without any loss in accuracy while being 2.59 × more energy efficient. LM can trade-off accuracy for additional improvements in execution performance and energy efficiency and compares favorably to an accelerator that targeted only activation precisions.