  Efficient training of large-scale graph neural networks (GNNs) has been
studied with a specific focus on reducing their memory consumption. Work by Liu
et al. (2022) proposed extreme activation compression (EXACT) which
demonstrated drastic reduction in memory consumption by performing quantization
of the intermediate activation maps down to using INT2 precision. They showed
little to no reduction in performance while achieving large reductions in GPU
memory consumption. In this work, we present an improvement to the EXACT
strategy by using block-wise quantization of the intermediate activation maps.
We experimentally analyze different block sizes and show further reduction in
memory consumption (>15%), and runtime speedup per epoch (about 5%) even when
performing extreme extents of quantization with similar performance trade-offs
as with the original EXACT. Further, we present a correction to the assumptions
on the distribution of intermediate activation maps in EXACT (assumed to be
uniform) and show improved variance estimations of the quantization and
dequantization steps.
