[josm-dev] Performance optimizations

Petr Nejedly Petr.Nejedly at Sun.COM
Mon Aug 25 22:30:48 BST 2008


Dirk Stöcker napsal(a):
> Hello,
> 
> Jörg Henne ist currently developing a set of performance improvements 
> for JOSM.
> 
> Find the patch here: http://www.dstoecker.eu/2008-08-21.patch
> 
> Here his note:
> ---
> Attached you'll find a patch against JOSM #813 which enhances the 
> performance of certain common operations: dragging nodes and ways and 
> selecting/deselecting elements. Please apply copious amounts of testing 
> and/or abuse.

I can't help myself but ask: Were there any measurable performance gains
by this change?

No matter how am I looking at the patch, even completely sober today :-),
all I see is worse performance for large datasets - the "real-time" damage
computation would iterate the whole data set several times for every repaint
(including style resolution), then slightly reducing the paint "aperture".
Or am I smoking something?

Well, maybe I have a different view on what "large dataset" is.
An order of magnitude different. Or two.
But when I'm mapping a larger trip over Czechia these days and download
a rectangle here and a rectangle there, it quickly adds up (note that
the project Czechia have recently imported all the forests).

-- 
Petr "Nenik" Nejedly, NetBeans/Sun Microsystems, http://www.netbeans.org
355/113 -- Not the famous irrational number PI, but an incredible simulation!




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