Gather perf counters for distributed jobs
Gather perf counters for distributed jobs

Summary: Set up a server node that periodically gathers values of all nodes' perf counters, allowing to publish them at once.

Reviewed By: dzhulgakov

Differential Revision: D4555116

fbshipit-source-id: 8e49ac8353b52b2be82aedf305762478e7fa687a

Yangqing/caffe2,sf-wind/caffe2,davinwang/caffe2,davinwang/caffe2,sf-wind/caffe2,bwasti/caffe2,Yangqing/caffe2,pietern/caffe2,sf-wind/caffe2,bwasti/caffe2,pietern/caffe2,Yangqing/caffe2,bwasti/caffe2,xzturn/caffe2,xzturn/caffe2,davinwang/caffe2,pietern/caffe2,bwasti/caffe2,sf-wind/caffe2,xzturn/caffe2,xzturn/caffe2,pietern/caffe2,pietern/caffe2,bwasti/caffe2,Yangqing/caffe2,davinwang/caffe2,Yangqing/caffe2,xzturn/caffe2,sf-wind/caffe2,davinwang/caffe2,caffe2/caffe2