[Qt-interest] Debugging QT application in KDevelop very slow

[Andreas Pakulat]

On 06.01.09 16:20:25, Jason Dolan wrote:
> Hello,
> 
> I'm using QT-4.5.0-beta1 (but have experienced the same problem in 
> 4.4.3) on Ubuntu-8.10.  My IDE of choice is KDevelop, but I find that 
> starting the debugger when working with my QT project is *extremely* 
> slow.  It'll take somewhere between a minute or two from the point I 
> start the debugger to when my program starts up.  After the program 
> actually starts it runs at an adequate speed and stepping through the 
> code is speedy enough.  Its just the initial startup cost that is 
> killing me.
> 
> As a test I ran the debugger (gdb) from the command line and it 
> responded as expected (about 5 secs to app start).
> 
> I thought I read somewhere the QTCreator had the same issue early on, 
> but it was resolved...
> 
> Does anyone have any hints on this?

You should ask this on the kdevelop user mailinglist
(www.kdevelop.org/index.html?filename=mailinglist.html)

And yes, it is relatively slow to load an app that links to large
libraries, especially when those have been built with debug symbols. If you
move the .debug files away it'll be a lot faster (but of course you won't
get accurate backtraces from Qt functions, not sure if this also affects
stepping). It also won't change in KDevelop3 and IIRC partly has to do with
the interface that GDB provides for applications to interact with it. 

In earlier versions of KDev3 settings breakpoints also caused heavy
slowdowns because KDevelop needed gdb to stop after each library load to
set the breakpoints (or try at least) so breakpoints in shared libs work
properly. This shouldn't be a problem anymore with KDev 3.5.3 or later and
a recent gdb (6.8 or newer).

That said I haven't used KDev3 debugger since quite some time now.

Andreas

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