Re: 25.3.1 netbsd; scp tramp has long delay on first connection

[Michael Albinus]

Van L <van@scratch.space> writes:

Hi,

> 7-8 line has the 75 second delay. The following is from an 'emacs -Q'

Yes. Lines 4-13 do check some features of your local ssh client.

> │ 4 17:58:00.710678 tramp-call-process (6) # ‘ssh -o ControlMaster’
> nil *temp*
> │ 5  17:58:00.722713 tramp-call-process (6) # 255
> │ 6  command-line line 0: missing argument.

This returns immediately.

> │  7 17:58:00.722880 tramp-call-process (6) # ‘ssh -o ControlPath=%C 0.0.0.1’ 
> nil *temp*
> │  8  17:59:15.790178 tramp-call-process (6) # 255
> │  9  Pseudo-terminal will not be allocated because stdin is not a terminal.
> │ 10  ssh: connect to host 0.0.0.1 port 22: Connection timed out

Here we have a time out, which causes the delay. The intention was to
get an immediate answer.

> │ 11 17:59:15.790435 tramp-call-process (6) # ‘ssh -o ControlPersist’
> nil *temp*
> │ 12  17:59:15.808515 tramp-call-process (6) # 255
> │ 13  command-line line 0: Missing ControlPersist argument.

This returns immediately, again.

Well, this is a known problem with some OpenSSH 7 versions, and fixed
already in more recent Tramp versions. The second ssh call in Tramp uses
"ConnectTimeout=1" additionally.

You can disable these tests by setting
tramp-use-ssh-controlmaster-options to nil.

Best regards, Michael.