Fedora 6 ssh X11 fast, Fedora 8 ssh X11 slow

[luther138]

I am having a problem with slow GUI's over an X11 connection.
The program i am running is matlab
It is installed on a F6 machine and a F8 machine(we've tried F9 as well)
No matter how we ssh -X to the F6 Machine we get a snappy fast gui when running matlab
(meaning I can connect to it from a F6 or F8 machine or even from OSX X11 and it runs great)

but on the F8 machine it moves like syrup, and become virtually unusable.

I am still trying to narrow down whether this is because of a different version of ssh or a different way that the windows are being drawn in Fedora 8. (Compiz is disabled and I have the latest JRE). I was hopeing someone has experienced similair problems and might be able to shed some light.

I have tried disabling all firewalls, ssh -YC, editing sshd_config to allow X11 forwarding, and many other non ssh related things, like installing latest JRE, disabling compiz, making sure graphics driver were running top notch. But the only way I can seem to get a fast interface is if matlab is running on F6.

Also it seems to be on the sshd end because when I use OSX X11 again it works snappy if being served from a Fedora 6, but slow as heck if being served from Fedora 8.

So I guess the question is , has there been any big changes to ssh since Fedora 6?
Or are the windows drawn differently now that would cause these problems?

Let me know what you guys think.

Thanks, Luther

[ppesci]

Only a guess, but, did you check the xorg.conf in both computers (F6 and F8)?. Are you using a native video drivers in both computers or has generic drivers?.

HTH

[ppesci]

Only a guess, but, did you check the xorg.conf in both computers (F6 and F8)?. Are you using a native video drivers in both computers or has generic drivers?.

HTH

[luther138]

the only difference is
Section "Device"
Driver "intel" # Fedora 6
Driver "nv" # Fedora 8

The FC6 machine has an integrated intel graphics driver
The F8 machine has an nvidia 8600GTS

Even tried the livna kmod-nvidia, no change

[ppesci]

There are some security concerns when you use port forwarding as states in ssh man pages.

Can you try to use the -Y option as substitute for -X option?

This must to be more efficient.

HTH

[luther138]

Already tired -Y and C

[drmirsky]

We have also found the same problem with using matlab over ssh with fedora, on several different machines with different hardware:

The matlab graphics and GUI are basically unusable over ssh with fedora 8 and above. Fedora 7 and below were perfect.

A forced installation of fedora 7 X11 libraries over fedora 8 and 9 seems to improve the performance.

Has anyone found a better solution? or even know what the problem is?

[rudi_m]

I found this thread because I got the same probs after updating from opensuse 10.2 to 10.3

I solved it here by recompiling libX11 (on suse it is the xorg-x11-libX11-7.2-75.x86_64.rpm)
with "configure --without-xcb"
Then copied libX11.so.6.2.0 and the link libX11.so.6 to
$MATLABROOT/sys/os/glnxa64/

(On 32bit system its MATLABROOT/sys/os/glnx86
and on Fedora you might have other version numbers)

If you dont want to recompile it then you could also unrpm the fedora 7 X11 libraries and copy all libs to $MATLABROOT/sys/os/glnxa64/
(or copy it to a seperate directory and set $LD_LIBRARY_PATH before starting matlab)

cu,
Rudi

[luther138]

It had been awhile since I had a chance to tackle this problem. But with the release of Fedora 10 I thought
it would be a good time to try again. Your advice was spot on. For anyone else with this problem, here is my
step by step

Install Fedora 10
Install Matlab
$ mkdir /tmp/libx11
$ cd /tmp/libx11
$ sudo yum groupinstall 'Development Libraries' 'Development Tools'
$ sudo yum install xorg-x11-xtrans-devel.x86_64
$ wget http://xorg.freedesktop.org/releases/current/src/lib/libX11-1.1.5.tar.gz
$ tar xvfz libX11-1.1.5.tar.gz
$ cd libX11-1.1.5
$ mkdir SharedLibraries
$ ./configure --without-xcb --prefix=/tmp/libx11/libX11-1.1.5/SharedLibraries
$ make
$ make install
$ cp ./SharedLibraries/libX11.so.* $MATLABROOT/sys/os/glnxa64/

And now my matlab is as snappy as if it was running on Fedora 6 :)

Also I don't see any reason why (if your not into compiling from source) you cant just take the libX11
rpm from fedora 7 and copy the said files into the same matlab folder, I just did this the compiling way
because I prefer to have the latest and greatest.

Thank again