[Paraview] Compositing

[Moreland, Kenneth]

With only 6 nodes, ParaView uses a tree compositing algorithm (at 8
nodes it switches to binary swap for better distribution).  So the first
node does indeed to some more compositing, but not much.  If you are
seeing a large difference in load balancing, I seriously doubt the
compositing is a major contribution.  Are you sure your data has an even
distribution to begin with?  Many readers do not necessarily give a good
distribution of data.  You could try running your visible surfaces
through D3 to balance them better, but if your animation changes the
geometry every frame you will lose more in redistribution than you gain
in load balancing.

-Ken

> -----Original Message-----
> From: Terry Jordan [mailto:tejj at hotmail.com] 
> Sent: Tuesday, March 21, 2006 1:08 PM
> To: Moreland, Kenneth; paraview at paraview.org
> Subject: RE: [Paraview] Compositing
> 
> The problem we have is that the data is starting to hit the 
> theshold of what a single workstation can handle, so we are 
> trying to setup a small vis cluster to allow us to look at 
> larger data.  Some of the data can be aninated and I am 
> trying to allow the animation to run as smoothly as possible 
> while using parallel paraview.  It just seemed to me that the 
> first node, the one you launch the mpi pvserver from seems to 
> be doing more work than all the other nodes and I thought it 
> would balance out the workload a little if one machine did 
> the compositing alone and not have a chunk of its own it 
> needed to render.  So in our case we have 6 nodes I want to 
> run mpi pvserver on and 1 node to run the client.  of those 6 
> nodes I figured we could have 5 pcs rendering chunks and one 
> compositing the chunks and squirting it to the client.
> 
> ----Original Message Follows----
> From: "Moreland, Kenneth" <kmorel at sandia.gov>
> To: "Terry Jordan" <tejj at hotmail.com>, paraview at paraview.org
> Subject: RE: [Paraview] Compositing
> Date: Tue, 21 Mar 2006 09:43:03 -0700
> 
> If there is not much difference between your server nodes and 
> client, you can very easily move all the geometry to the 
> client and render locally.  In "3D View Properties" under 
> "LOD Parameters" there is an entry titled "Composite."  That 
> entry has a slider bar that represents the threshold at which 
> geometry is moved to the client.  If necessary, you can move 
> that slider to the right so that it collects bigger 
> geometries.  You can also unclick the box to turn off 
> compositing altogether and always collect polygons.  This 
> will backfire on you, however, if you are rendering a large 
> quantity of data.
> 
> If you really want the geometry to be collected on one of the 
> server nodes, you will have to run in client/render 
> server/data server mode.
> Make the data server span all 6 machines and the render 
> server reside on one of them.  It should be OK to have a 
> render server and data server share a node so long as memory 
> is not a problem.  This configuration will force all the 
> geometry to be pushed to the single render server node where 
> it will be rendered and delivered to the client.
> 
> Performance-wise is this a good idea?  That depends on your 
> system configuration.  Unless your server rendering hardware 
> is way faster than your client and your cluster interconnect 
> really sucks, then probably not.  I recommend experimenting 
> with the "Composite" and "Subsample Rate" options first to 
> try to find a good compromise amongst rendering speed, image 
> quality, and data management.
> 
> -Ken
> 
>  > -----Original Message-----
>  > From: paraview-bounces+kmorel=sandia.gov at paraview.org
>  > [mailto:paraview-bounces+kmorel=sandia.gov at paraview.org] 
> On  > Behalf Of Terry Jordan  > Sent: Tuesday, March 21, 2006 
> 9:03 AM  > To: paraview at paraview.org  > Subject: [Paraview] 
> Compositing  >  > I am running paraview (pvserver) using MPI 
> on 6 machines (a  > small rendering or vis cluster) and 
> piping it back to a  > single display using pvclient.  I am 
> wondering if I can  > specifiy one pc to only do the 
> compositing.  So instead of  > one pc rendering a portion of 
> the data and compositing, one  > could just composite.  Is 
> this feasible and performance-wise  > would it be a good idea?
>  >
>  > Thanks in advance.
>  >
>  >
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