[Interest] QTableWidget performance

Paul England pengland at cmt-asia.com
Fri Mar 16 01:20:03 CET 2012

Hi.  Thanks for the reply.


> The proper answer to this is that you need to run this through a
> profiler. You know, premature optimization...
> If your code runs on Linux, you should take a look at KCacheGrinder.
Indeed, and this has been mentioned by someone else on the team... right 
now, it's just an issue of time.  Lots of important stuff on the table.

> Impossible to answer, when you don't know what the problem is.
> I *really* don't like the *Widget versions, and will always tell my
> customers to go with a proper model (not a QStandardItemModel based),
> but that's for other reasons.

I will be looking into Model/View for future projects, but *most* stuff 
until now is a rather small set of data, that changes somewhat rapidly, 
and from different sources. Definitely beyond the scope of this email.
>> My main resistance to this is that while the data is somewhat simple, I
>> already have a pretty complex system to filter what should be displayed
>> and what shouldn't, what colors should be displayed for visible items,
>> what font to use, and whether a sound should be played or not. This is
>> all configured by the user in the GUI.
> Aha, that might very well be the reason. You should try and remove the
> filter code completely and see if this solves the problem. Those filters
> can be very expensive to calculate.
The checks themselves are pretty light (usually boolean or an integral 
comparison).  The actions are another story, but even then, it's almost 
always a cell coloration.  But, for this particular instance I was 
checking, he has just a plain vanilla view.  No checks, no colors, no 
sounds, no nothing... just lag.  :/

The main difference is hardware, and the Window Manager.  My guess is 
it's hardware.  I think we'll upgrade first and then revisit the problem. :)

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