  Sparsity has become one of the promising methods to compress and accelerate
Deep Neural Networks (DNNs). Among different categories of sparsity, structured
sparsity has gained more attention due to its efficient execution on modern
accelerators. Particularly, N:M sparsity is attractive because there are
already hardware accelerator architectures that can leverage certain forms of
N:M structured sparsity to yield higher compute-efficiency. In this work, we
focus on N:M sparsity and extensively study and evaluate various training
recipes for N:M sparsity in terms of the trade-off between model accuracy and
compute cost (FLOPs). Building upon this study, we propose two new decay-based
pruning methods, namely "pruning mask decay" and "sparse structure decay". Our
evaluations indicate that these proposed methods consistently deliver
state-of-the-art (SOTA) model accuracy, comparable to unstructured sparsity, on
a Transformer-based model for a translation task. The increase in the accuracy
of the sparse model using the new training recipes comes at the cost of
marginal increase in the total training compute (FLOPs).
