OpenSSH and ControlMaster

I’ve been using tramp lately. It’s very cool but also often very slow. Yesterday I found this description of ControlMaster on

“OpenSSH 4.0 introduced an interesting new feature called ControlMaster that allows it to reuse an existing connection to a remote host when opening new connections to that host. This can significantly reduce the amount of time it takes to establish connections after the initial connection. Let’s see how this can help you work faster, and how to start using ControlMaster right away.”

As the article discusses, I tried timing 10 calls to

ssh my-host hostname 

First without ControlMaster and then with it. The results:

  • No ControlMaster – 0.218 user
  • ControlMaster – 0.038 user

Yozaa. I haven’t been tramping with it so I’m not sure how this will translate to my day-to-day. Still, I have hope.