Comment 0 for bug 1521053

[Impact]

Ubuntu VM in Azure has network performance issue when check by using netcat&nload
Normal bandwidth is 50MB/s ~ 100MB/s, but it's 0.3MB/s when dropping happens

[Fix]

Upstream development
0d158852a8089099a6959ae235b20f230871982f ("hv_netvsc: Clean up two unused variables")

It's affected over 3.19.0-28-generic (vivid)

With this commit, I confirmed that the problem has gone by the testing.

[Testcase]

This is only for Azure service.

Make 2 vms on North Europe, West Europe and run below test script

NE

 while true; do netcat -l 8080 < /dev/zero; done;

 nload -u M eth0 ( need nload pkg )

WE

 for i in {1..1000}
 do
  timeout 30s nc NE_HOST 8080 > /dev/null
 done

Network performance dropping can be seen frequently