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<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>Raashid,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>First, let me
assure you that ParaView’s parallel visualization and rendering are
efficient and scalable. We have been able to use ParaView to visualize 6
billion cell grids and have clocked rendering speeds of over 8 billion polygons
per second (albeit with much larger clusters than you have set up).<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>As far as your
problems are concerned, I’m going to have to do a lot of guessing because
I cannot replicate your problem and there are missing pieces of information.
Looking at your mpirun command, it appears that the DISPLAY variable is set to
the same value on every process. That is, all processes in the ParaView
server are creating a remote (for them) X window on 10.101.11.71. If that
is the case, it is very, very bad. Basically, that would mean that all of
the rendering is being funneled into one computer. Thus, instead of
actually getting parallel rendering, you are getting serial rendering plus the
added overhead of moving OpenGL primitives and images across the network plus
the standard overhead of parallel rendering. Note that because you are
only using 3 computers, I would not expect the parallel gains to be much higher
than the natural overhead of the parallel algorithms. If your computers
are using a standard Ethernet connection, the relatively high latency and low
bandwidth will further erode the parallel gains.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>The fact that
your parallel job is crashing when you have a parallel job with a sizeable data
set suggests that you might not be using parallel rendering at all. You
can shut off parallel rendering with the 3D view properties or ParaView will
shut it off for you if the server cannot create the appropriate rendering
windows. When parallel rendering is shut off, ParaView does the only
thing left: funnel all of the geometry to the client.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>Verify that you
are actually doing parallel rendering. Start by running in client/server
mode (don’t bother with parallel standalone: its usefulness is basically
limited to debugging). Go to 3D View Properties, verify that the checkbox
next to “Composite” is checked and move the slider all the way to
the left (0 MBytes). If everything is working right, parallel rendering
should now always be used. The easiest way to verify that is to observe
the subsampling, which only happens on interactive rendering when rendering in
parallel. Make sure that the checkbox next to “Subsample Rate”
is checked and move the slider to the right to 4 Pixels or more. Now when
you rotate your 3D rendering, it should look pixilated.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>Offhand, I
cannot think of another reason for your memory failures. I just used the
Wavelet source to create a 125,000,000 cell structured mesh on three nodes of
our visualization cluster (each with 1 MB each), then created 5 isosurfaces
(~7.4 million cells and ~3.7 points) and rendered it just fine.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>One last piece
of advice: don’t run D3 on your structured data. ParaView can
balance your structured data without any help. D3 is designed for
unstructured data. The first thing it will do is convert the structured
data to unstructured, which is a much less efficient representation. It
makes more sense to run D3 on the output of the contour filter, but that is
probably not worthwhile unless the contour is very big and very unbalanced.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'>-Ken<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=maroon face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:maroon'><o:p> </o:p></span></font></p>
<div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'>
<div>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> paraview-bounces+kmorel=sandia.gov@paraview.org
[mailto:paraview-bounces+kmorel=sandia.gov@paraview.org] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Raashid Baig<br>
<b><span style='font-weight:bold'>Sent:</span></b> Thursday, July 05, 2007
12:25 PM<br>
<b><span style='font-weight:bold'>To:</span></b> paraview@paraview.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Paraview] Newbie
question about paraview's parallel visualization procedure</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>I am a
newbie to parallel visualization and ParaView in general, I<br>
have some doubts which may be very fundamental. <br>
<br>
I am using ParaView2.6.X and trying to do some performance analysis<br>
and dataset limit of ParaView in general as a part of an academic<br>
project. I want to see what are the gains in CPU & memory usage and<br>
time required to render a particular dataset when ParaView is run in<br>
parallel. All machines are Intel Core Duo 2, 2GB DDR2 RAM, and 2GB<br>
swap, all machines have NVidia 7series graphics cards and have<br>
Debian/Ubuntu Linux<br>
<br>
I have structured data-sets with point attributes in form of VTK<br>
legacy files. When I run paraview in stand-alone mode on a single<br>
machine, I am able to draw 5 iso-surface for structured grid datasets<br>
upto 5 million points. But when I put the same VTK legacy files on 3<br>
different computers (all have ParaView 2.6.X installed) and run<br>
ParaView through LAM/MPI in distributed stand alone mode (as described<br>
in the ParaView book) on these 3 machines, the performance decreases<br>
for the isosurface case. Not only does the time taken to render final<br>
image, cpu/memory usage increase, I am only able to visualize till 1<br>
million grid points. After 1 million point the get an error (this<br>
particular error is for a dataset of 2 million) :<br>
<br>
raashid@ged:~/src/cvs/paraview-unix/bin$ mpirun -np 3 -x
DISPLAY=10.101.11.71:0.0 ./paraview<br>
ErrorMessage<br>
# Error or warning: There was a VTK Error in file: /home/raashid/src/cvs/ParaView/VTK/Common/vtkDataArrayTemplate.txx
(266)<br>
vtkIdTypeArray (0xe041768): Unable to allocate 59135376 elements of size 4
bytes.<br>
ErrorMessage end<br>
-----------------------------------------------------------------------------<br>
One of the processes started by mpirun has exited with a nonzero exit<br>
code. This typically indicates that the process finished in error.<br>
If your process did not finish in error, be sure to include a "return<br>
0" or "exit(0)" in your C code before exiting the application.<br>
<br>
PID 16283 failed on node n0 (10.101.11.71) due to signal 11.<br>
-----------------------------------------------------------------------------<br>
<br>
I get the same error as above if I use a D3 filter before applying the<br>
iso-contour.<br>
<br>
<br>
Following the ideas of a technical report I tried to open the VTK<br>
legacy file when ParaView server was running on 3 different computers<br>
and the client was running on a different computer, apply the D3<br>
filter and then save the file as PVTK unstructured grid format<br>
(*.pvtu, with 1 ghost levels), close the paraview, start a fresh<br>
paraview session with the same configuration (ParaView server was<br>
running on 3 different computers and the client was running on a<br>
different computer) load the master *.pvtu file and do the same<br>
iso-contour example as above, the server again crashes and displays<br>
the following error.(this particular error is for 2.5 million grid<br>
points)<br>
<br>
On the server side I get the message :<br>
------------------------------------------------------------------------------<br>
raashid@ender:~/src/cvs/paraview-unix/bin$ mpirun -np 3 -x
DISPLAY=10.101.11.71:0.0 ./pvserver<br>
Listen on port: 11111<br>
Waiting for client...<br>
Client connected.<br>
Process id: 0 >> ERROR: In
/home/raashid/src/cvs/ParaView/VTK/Common/vtkDataArrayTemplate.txx, line 95<br>
vtkIdTypeArray (0xd243258): Unable to allocate 75216436 elements of size 4
bytes.<br>
<br>
Process id: 0 >> ERROR: In
/home/raashid/src/cvs/ParaView/Servers/Common/vtkProcessModule.cxx, line 1187<br>
vtkProcessModule (0xb395560): Exception: Insufficient memory exception.<br>
------------------------------------------------------------------------------<br>
<br>
On the client side I get the message<br>
-------------------------------------------------------------------------------<br>
raashid@ged:~/src/cvs/paraview-unix/bin$ ./pvclient --server-host=10.101.11.72<br>
Connected to server<br>
ErrorMessage<br>
# Error or warning: There was a VTK Error in file:
/home/raashid/src/cvs/ParaView/Servers/Common/vtkProcessModule.cxx (1171)<br>
vtkProcessModule (0xc0c7530): Received exception from server: Insufficient
memory exception.<br>
ErrorMessage end<br>
ErrorMessage<br>
# Error or warning: There was a VTK Error in file:
/home/raashid/src/cvs/ParaView/Servers/Common/vtkServerConnection.cxx (67)<br>
vtkServerConnection (0xc0ee1b8): Server Connection Closed!<br>
ErrorMessage end<br>
--------------------------------------------------------------------------------<br>
<br>
Am I using the wrong file type, if yes what should I use ? <br>
Is there some threshold limit I am violating ?<br>
<br>
Please help me with this problem, because I am in serious trouble. <o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
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