sftp performance problem, cured by TCP_NODELAY

[Miklos Szeredi]

> http://bugzilla.mindrot.org/show_bug.cgi?id=556 has been there for a
> while, but nobody commented on it.

Ah.

So TCP_NODELAY is already set for interactive sessions.  I hadn't
noticed that.

It's actually pretty stupid I think, as Nagle (TCP_NODELAY off) _only_
makes sense for _interactive_ sessions.

So it should be the other way round as it is currently.

But unconditionally setting TCP_NODELAY should at least cure the sftp
performance problem.  The patch in comment #9 looks fine.

Longer term I think you should consider adding "NoDelay" and maybe
"NoDelayInteractive" bool options, and _not_ setting nodelay on
interactive sessions by default.

Miklos