valgrinding the Gideon

[Kuba Ober]

> > Did anybody valgrind the Gideon yet? I've recently found out that
> > it's a real
> > blessing to do so every once in a while to a code that's still evolving.

> Harry and I did a little valgrinding a few weeks ago, but it was mostly for
> startup stuff.  It chugged really slowly on my P4-2800 and I wasn't able to
> do a lot with it.  But we did clear up some minor glitches with it.

Hmmm... I'm valgrinding a Qt program that, apart from everything else, 
processes about 390 data points per second from a realtime USB device. Tha 
includes realtime display, etc.

On my 500MHz PIII it runs quite acceptably -- slowdown is about 25x, which 
given that the program is pretty fast as it is, makes it quite easy to use.

Did you use the latest valgrind?

I've also found that not doing unnecessary things (mouse movements, etc) while 
waiting for an event to be processed (say after a key click / button press) 
can also speed things up noticeably. After all, those mouse move events are 
processed by the xlib and qt that run inside valgrind's vm.

If things are really so bad as to be useless on a P4-2800, it may mean that 
there are some race conditions in Kdevelop and that things that were supposed 
to be done once are done many times.

Running kcachegrind on valgrind's cache&trace output will pinpoint the 
culprits.

Cheers, Kuba Ober