Add throughputs metric and enable in cpu userbenchmark (#1727)
Summary:
Add throughputs metric in torchbench model metrics, enable throughputs metric in cpu userbenchmark.
Work for roadmap https://github.com/pytorch/benchmark/issues/1293 to add fps-like report in cpu userbenchmark.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/1727
Reviewed By: FindHao
Differential Revision: D46684920
Pulled By: xuzhao9
fbshipit-source-id: fa0042d5bd3660fb21e700d6fe0512fcd4c8844c