Nagle & delayed ACK strike again

[Miklos Szeredi]

This time the problem is that the ssh server only sets TCP_NODELAY for
interactive (tty) sessions or if X11 forwarding is enabled.  Neither
of which are true for the use of the sftp subsystem.  This hurts
upload performance for sftp/sshfs.

I'm not sure why this hasn't cropped up earlier.  Were there any
TCP_NODELAY related changes in the sshd code recently?

Is there a reason not to enable NODELAY unconditionally?  Any reason
why the server end is different from the client (where NODELAY is now
uncoditionally enabled) in this respect?

Thanks,
Miklos