icefox tests issues

Matt Rogers mattr at kde.org
Wed Oct 20 19:35:48 CEST 2004


On Wed, Oct 20, 2004 at 07:26:51PM +0200, Juergen Pfennig wrote:
> On Wednesday 20 October 2004 17:42, rgfernandes wrote:
> > Hi,
> > I saw the page of icefox tests and play a little with code
> > from kde 3.3.1.
> > My first test was to change all occurrencies in kdelibs and
> > kdebase packages of it++ in loops and change to ++it. For my
> > surprise, I make a huge optimization in kde. My konqueror
> > took about 10 seconds to open my /usr/lib directory. After
> > the changes, it takes about 2 seconds. Several other
> > applications open and works very faster.
> 
> That's hard to believe. An optimizer should see in most it++ cases that the 
> value of it was not used and therefore optimize the expression. The ++it is 
> often discussed in text books - but today it's only a question of personal 
> taste.
> 

AFAIK, using it++ in Qt/KDE is worse because a temporary object is
created, but i could be _completely_ wrong. So this _might_ (very slim
possibility) cause a speedup, but caching the value of end() might have
more effect.

> Benchmarking is a quite complicated thing. Are you sure that you did not 
> benchmark the linux kernel's caching mechanisms?
> 
> Yours J??rgen


More information about the Kde-optimize mailing list