[vtkusers] threads and vtkSynchronizedTemplates

[Dave Semeraro]

Hello there,

I am using vtkSynchronizedTemplates3D to generate isosurface geometry from a
structured points data set. I am running the test on a dual 1.4ghz athlon 
processor linux system
running the 2.4.18-xfs kernel. I am timing the results using the 
vtkTimerLog class. It seems to
make little difference in time whether I use 1 or 2 threads to do the test. 
In fact the 2 thread
case seems to run slightly slower. The isosurface value I choose generates 
over 800,000
polygons and takes about 0.8 seconds to complete so I dont think it is a 
timer resolution
problem. I have verified that setting the number of threads does indeed 
cause both cpus to
be used ( verified via top output).  I must be doing something wrong. Why 
bother with threading
if you see no difference in speed? Has anyone else seen similar results? 
Can anyone explain
what I am doing wrong?

Best Regards,
Dave Semeraro

Dave Semeraro Ph.D.
Visualization and Virtual Environments Group
NCSA University of Illinois
605 E. Springfield Ave.
Champaign, IL 61820
Semeraro at ncsa.uiuc.edu
(217) 244-1852