Java performance awful, any ideas?

Kai Wollweber wollw at ki.tng.de
Fri Nov 14 15:05:36 GMT 2008


Am Freitag, den 14.11.2008, 09:44 -0500 schrieb Todd O'Bryan:

> I'm trying to run BlueJ (http://www.bluej.org), a fairly modest Java
> IDE for students. It runs fine on the servers, on my Ubuntu laptop and
> desktop, but on the clients it's as slow as molasses.

Rhere is already a bug report at launchpad about this issue:

https://bugs.launchpad.net/ubuntu/+source/ia32-libs/+bug/277069


I asked Juha in ltsp-discuss mailing-list and his answer gives us a
workaround:

> ----- "Kai Wollweber" <wollw at ki.tng.de> kirjoitti:
> > yesterday I recognized the problem of slow java applications on our
> ltsp
> > clients. In our case the java program "geonext" is unuseable but
> > importand for our school. I found your solution posted some weeks
> > ago:
> >> The sluggishness of some Java applications can be solved in Ubuntu
> >> Hardy by replacing the /usr/lib32/libX11.so.6.2.0 file in Hardy
> with
> >> the version in Gutsy (presuming Firefox and Java are 32-bit
> versions, so
> >> they use 32-bit libraries).  The main difference between these
> versions
> >> appears to be that the Hardy version links
> to /usr/lib/libxcb-xlib.so.0
> >> and /usr/lib/libxcb.so.1, and the older version does not.  Similar
> change
> >> may work as well with other LTSP distributions that are affected by
> this.
> 
> > 1.) How can a single file be replaced between different Ubuntu
> versions?
> 
> Simply replacing the file (with cp) should be enough, but in
> case updates should happen to ia32-libs package that contains the
> /usr/lib32/libX11.so.6.2.0 file, those updates will overwrite the
> changed file.  dpkg-divert can be used to solve this problem, it can
> be used to divert file updates to another place (in this case, because
> the file is a shared library, it should not be in the same directory,
> otherwise ldconfig will link to the wrong file).
> 
> You might want to test by simply installing the gutsy version of
> ia32-libs package, it should work, but I don't recommend that as a
> permanent solution (it will change many other libraries as well).
> 
> > 2.) Where can I get the file from Gutsy?
> 
> http://packages.ubuntu.com/gutsy-updates/amd64/ia32-libs/download
> 
> You can unpack deb-archives with (IIRC):
> 
> (mkdir tmp && cd tmp && ar x ../ia32-libs_2.1ubuntu4_amd64.deb && \
>    tar -zxf data.tar.gz)
> 
> You'll find the file there.
> 
> > 3.) Are there side effects that probably can affect the system?
> 
> Perhaps, but I'm not aware of any.
> 
> > 4.) Am I right that the file needs to be replaced in the ltsp
> chroot?
> 
> No, X-clients use this library, so it needs to be replaced in the ltsp
> server environment, NOT in the image that is served to terminals.
> 
> I hope this helps.
> 
> Juha




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