Re: ssh -X forwarding

[James Cloos <cloos@jhcloos.com>]

>>>>> "Jan" == Jan Teichmann <jan.teichmann@gmail.com> writes:

Jan> i'm forwarding my emacs session with "ssh -X -C" and it works, but
Jan> the emacs forwarding is so slowly. is their a possibility to cache
Jan> the data on the client computer, that scrolling and so on gets faster?

The best way to speed up X over ssh is to use NX.  The nx protocol does
a much better job of compressing the X11 stream than zlib can do, and it
also does some caching as well.

Other than that, and especially if you are using server-side fonts (ie,
if you are using any version of emacs other than the unicode2 branch),
you could try running in a monochrome visual.  Check out the visualClass
X keyword in the manpage or info.

Perhaps something like this in the ~/.Xdefaults-${HOSTNAME} file on the
remote box would do it:

emacs.visualClass: TrueColor-1

For ${HOSTNAME} above use whatever the HOSTNAME env var is set to on
that box; this will ensure the libX11 there loads that file in when
you run anything linked to it.  Also, of course, choose a visualClass
that your X server supports (see the output of xdpyinfo(1) for those.)

Forcing emacs to use a 1 bit visual should reduce the traffic across the
network quite a bit when compared to a 16, 24 or 32 bit visual.

Finally, if you can, it may be better to use an emacs compiled against
the athena toolkit than the GTK toolkit.  And you probably also want to
turn off the toolbar.  So I'd also put:

emacs.toolBar: off

in the remote's ~/.Xdefaults-${HOSTNAME} file.

If you are using the unicode-2 branch (now version 23.0.60), try also
adding:

emacs.FontBackend: x
emacs.font: -misc-fixed-medium-r-normal--18-120-100-100-c-90-iso10646-1

(but choose your prefered font).

The antialiased fonts are great, but the monochrome fonts will be *much*
faster across a slow net link.

Having said all of that, I just tried it and even though the syntax is
correct and xdpyinfo(1) says my server supports both TrueColor and
DirectColor in depths 24, 1, 4, 8, 15, 16, 32 only depth 24 actually
works for me.  [SIGH]

I'll post this anyway for the archive, but it looks like you either have
to start the server in monochrome mode or use NX.

Your distribution probably has packages for NX.  Otherwise look at:

http://www.nomachine.com/
http://freenx.berlios.de/
http://www.2x.com/terminalserver/

(The latter two are GPL.)

-JimC
-- 
James Cloos <cloos@jhcloos.com>         OpenPGP: 1024D/ED7DAEA6