Improve the quality of moco train (#659)
Summary:
Add comments to moco to specify where the batch size comes from.
The moco paper is using batch size of 256 over 8 GPUs, which is 32 per GPU.
Source: https://arxiv.org/pdf/1911.05722.pdf
Pull Request resolved: https://github.com/pytorch/benchmark/pull/659
Reviewed By: xuzhao9
Differential Revision: D33194511
Pulled By: aaronenyeshi
fbshipit-source-id: 451207ec782de5f51c79140124e29e013680b67b
