[Qgis-developer] Approximate reprojection for vectors

[Marco Hugentobler]

Hi Martin

> how did you profile? Using callgind, oprofile or directly measuring
> time?

It was with callgrind.

> the time spent within postgres provider while waiting for server to
> return the features may not be considered.

That might be a valid point. Is it better to use oprofile for the waiting time?

In any case, the other servers in the benchmark had to fetch the features from 
the same database. So there must be very performance critical differences in 
the other parts of the code. As you might know, QGIS didn't really win first 
price...

Regards,
Marco

Am Sonntag, 2. Oktober 2011, 22.15:55 schrieb Martin Dobias:
> On Sun, Oct 2, 2011 at 4:33 PM, Marco Hugentobler
> 
> <marco.hugentobler at sourcepole.ch> wrote:
> > I did a lot of profiling for the FOSS4G WMS benchmark (osm data,
> > reprojected to google crs, complex symbology with a lot of rules). The
> > pattern was mostly the following:
> > the rendering itself (QPainter->drawPolyline) was the most time consuming
> > operation (appr. 50% of rendering time), next was evaluation in rule
> > based renderer (20% of time), getNextFeature in PostgresProvider 10%,
> > coordinate transformation 10%.
> 
> Marco,
> 
> how did you profile? Using callgind, oprofile or directly measuring
> time? If you used callgrind the results may be significantly skewed:
> the time spent within postgres provider while waiting for server to
> return the features may not be considered.
> 
> Regards
> Martin


-- 
Dr. Marco Hugentobler
Sourcepole -  Linux & Open Source Solutions
Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee