[Bug 1077965] [NEW] qt4 applications over X forward run slower than with Ubuntu 10.04 LTS

[Stefan Pielmeier]

Public bug reported:

use case: 
- shared desktop where users log on via ssh with X forwarding and local area network with 1GBit/s 
- machine is a Ubuntu server installation, originally 64bit Ubuntu 10.04, upgraded to 12.04
- the multiarch libraries for 32 bit are installed (see package list attached)

expected behaviour:
- the remote started qt apps that use X forwarding shall run at least the same speed with Ubuntu 12.04 and 10.04. 

observed behavior: 
- after upgrade from 10.04 64bit to 12.04 64bit, all remotely X forwarded qt applications (like kdbg) are significantly slower than on 10.04 (factor 3-9);
- another (multiarch) 64 bit Ubuntu machine that was a new 12.04 install show similar bad performance with qt applications over X forward.
- therefore it can be expected that the upgrade itselv isn't the problem, but more something in Ubuntu 12.04 that is slowing down qt apps that are run over X forward.

hardware: i7, 8GB RAM, SSD harddisks

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: libqtcore4 4:4.8.1-0ubuntu4.3
ProcVersionSignature: Ubuntu 3.2.0-32.51-generic 3.2.30
Uname: Linux 3.2.0-32-generic x86_64
ApportVersion: 2.0.1-0ubuntu14
Architecture: amd64
Date: Mon Nov 12 15:23:33 2012
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 LANGUAGE=en_US:en
SourcePackage: qt4-x11
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: qt4-x11 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug precise running-unity

** Attachment added: "the 'dpkg --get-selections' output of the affected machine"
   https://bugs.launchpad.net/bugs/1077965/+attachment/3431327/+files/yoda-selections.txt

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Title:
  qt4 applications over X forward run slower than with Ubuntu 10.04 LTS

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