Java performance awful, any ideas?

[Todd O'Bryan]

Does anyone have any idea what the bug might be and if it's still
present in intrepid? I'll try the fix on Monday and see what
happens...

On Fri, Nov 14, 2008 at 10:05 AM, Kai Wollweber <wollw at ki.tng.de> wrote:
> 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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