Nagle & delayed ACK strike again

[Rick Jones]

Miklos Szeredi wrote:
> 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?

I suspect that past discussions might be interesting reads - should be 
an an archive somewhere I suspect.

My personal stance is that 99 times out of ten, if an end-user 
application speeds-up when it sets TCP_NODELAY, it implies the end-user 
application is broken and sending "logically associated" data in 
separate send calls.

Now, if something is simply acting as a pipe, and passing along what it 
is given, then the above is not my opinion.  But then, when something is 
acting as a pipe, it isn't what I would call the "end-user application" 
- it is part of the plumbing in the middle.

rick jones