[Paraview] Paraview and Multicore

Guido Staub gstaub at udec.cl
Tue May 18 13:17:06 EDT 2010 

Using Process ID Scalars results in an Data Array ProcessId which in
case of np 3 ranges from 0 to 2 (and from 0 to 3 in case of np 4). I
have selected colorBy ProcessID to see if the input is well balanced or
not, unfortunately all the points have the same color. So I conclude
that the data is not well balanced, right?

If I apply the D3 filter I almost see the same results. The only
difference I have noticed is that there is no new Data Array. 

Delaunay 2D is now about three times faster after I applied D3 filter.
However I do not like the resulting triangulation, seems like some
isosurfaces have been calculted.

Guido

Am Thu, 13
May 2010 20:48:11 -0400 schrieb Andy Bauer <andy.bauer at kitware.com>:

> Process Id Scalars doesn't do any load balancing, it just shows what
> cells are assigned to what process.  You can try the D3 filter to do
> actual load-balancing (your reader may already be doing this though
> in which case you would see the same results from a Process Id
> Scalars filter used after the D3 filter).  I'm not that familiar with
> the internals of Delauney2D for distributed points but it's quite
> possible that for the set of points you have that the partitioning is
> not appropriate.  As Ken said, using the Process Id Scalars to see if
> the input is fairly well balanced.
> 
> Andy
> 
> On Thu, May 13, 2010 at 3:33 PM, Guido Staub <gstaub at udec.cl> wrote:
> 
> > Process Id Scalars didn't do the trick, still no performance gain
> > with Delaunay 2D.
> > My data is stored in a h5 file which gets loaded through a xdmf
> > file. After running the Process Id Scalars filter I do not see any
> > changes in the distribution of the data. However I guess that they
> > are already "evenly distributed" by default.
> >
> > So maybe exporting the file to an other format will do it or is
> > there a problem with the Delaunay implementation in general when
> > running in parallel?
> >
> > Guido
> >
> >  Am Thu, 13 May 2010 15:08:04
> > -0600 schrieb "Moreland, Kenneth" <kmorel at sandia.gov>:
> >
> > > Ah, I see.  It sounds like your data is not balanced.  Many of the
> > > "non parallel" file formats will do something stupid when loading
> > > data in parallel.  For example, they might load everything on
> > > process 0 or load everything everywhere.  (And now that I think
> > > about it, the Delaunay filter may have trouble in parallel.)
> > >
> > > Try running the "Process Id Scalars" filter on your data.  Do the
> > > points look evenly distributed?
> > >
> > > -Ken
> > >
> > >
> > > On 5/13/10 10:17 AM, "Guido Staub" <gstaub at udec.cl> wrote:
> > >
> > > Well if I start pvserver by mpirun -np 4 pvserver I have 3 cores
> > > running at almost 100%. Now I connect to the server and start a
> > > Delaunay 2D calculation on one of my datasets. As a result all of
> > > the 4 cores are showing 100%. However I assume that there is only
> > > one core doing the job, because on the one hand calculation is
> > > really slow. I have done similar processing on an other PC (an
> > > outdated one) and there is no significant performance advantage
> > > as one would expect. And on the other hand, running pvserver with
> > > e.g. -np 2 results in 100% for 2 CPUs when starting the Delaunay
> > > 2D calc (1 core at 100% when cpu is idle).
> > >
> > > Guido
> > >
> > >
> > >  Am Thu, 13 May 2010
> > > 12:39:43 -0600 schrieb "Moreland, Kenneth" <kmorel at sandia.gov>:
> > >
> > > > I am afraid I simply don't understand the question.  You said
> > > > in (1) that you have three cores running at 100%.  Then in (2)
> > > > you said that you only have one core running.  Is it happening
> > > > when you start the client, connect the client to the server,
> > > > launch the server from the client, or something else?  Is
> > > > something running or is the client sitting idle waiting for the
> > > > user?
> > > >
> > > > -Ken
> > > >
> > > >
> > > > On 5/13/10 8:15 AM, "Guido Staub" <gstaub at udec.cl> wrote:
> > > >
> > > > Thanks Ken, but I have already read this thread, therefore I
> > > > started the client process anyway without taking care of cpu
> > > > usage for now.
> > > >
> > > > However my second question still keeps me busy. Isn't it
> > > > possible to use all 4 cores?
> > > >
> > > > Guido
> > > >
> > > > Am Thu, 13 May 2010
> > > > 10:29:13 -0600 schrieb "Moreland, Kenneth" <kmorel at sandia.gov>:
> > > >
> > > > > The question about why the pvserver processes are always at
> > > > > 100% CPU comes up frequently on the mailing list (such as
> > > > > http://www.paraview.org/pipermail/paraview/2008-December/010338.html
> > ).
> > > > > I've added some information to the Wiki about it to provide an
> > > > > explanation:
> > > > >
> > http://www.paraview.org/Wiki/Setting_up_a_ParaView_Server#Server_processes_always_have_100.25_CPU_usage
> > > > >
> > > > > -Ken
> > > > >
> > > > >
> > > > > On 5/13/10 5:06 AM, "Guido Staub" <gstaub at udec.cl> wrote:
> > > > >
> > > > > Hi all,
> > > > >
> > > > > I have succesfully compiled Paraview with MPI support on my
> > > > > Workstation (Quad Core). I have read that paraview runs
> > > > > serial, pvserver parallel, so I started the server by mpirun
> > > > > -np 4 pvserver and connected through X. Everything seems to
> > > > > work fine.
> > > > >
> > > > > But there are two strange behaviours I have noticed:
> > > > >
> > > > > 1. CPU usage on workstation is almost 100% on three of the
> > > > > four cores although no client is connected (when I type
> > > > > mpirun -np 3 pvserver there are 2 out of 4 running at 100%;
> > > > > with -np 2 only 1). I have noticed this using MPICH2 and
> > > > > OpenMPI.
> > > > >
> > > > > 2. When I now start a client process the server uses only one
> > > > > core (-np 4/3/2/1). Why?
> > > > >
> > > > > Does MPI not work on multicore systems as on multiprocessor
> > > > > systems or is this a Paraview issue?
> > > > >
> > > > > Thanks,
> > > > > Guido
> > > > > _______________________________________________
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> > > > >
> > > > >
> > > > >
> > > > >    ****      Kenneth Moreland
> > > > >     ***      Sandia National Laboratories
> > > > > ***********
> > > > > *** *** ***  email: kmorel at sandia.gov
> > > > > **  ***  **  phone: (505) 844-8919
> > > > >     ***      web:
> > > > > http://www.cs.unm.edu/~kmorel<http://www.cs.unm.edu/%7Ekmorel>
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > >    ****      Kenneth Moreland
> > > >     ***      Sandia National Laboratories
> > > > ***********
> > > > *** *** ***  email: kmorel at sandia.gov
> > > > **  ***  **  phone: (505) 844-8919
> > > >     ***      web:
> > > > http://www.cs.unm.edu/~kmorel<http://www.cs.unm.edu/%7Ekmorel>
> > > >
> > >
> > >
> > >
> > >
> > >    ****      Kenneth Moreland
> > >     ***      Sandia National Laboratories
> > > ***********
> > > *** *** ***  email: kmorel at sandia.gov
> > > **  ***  **  phone: (505) 844-8919
> > >     ***      web:
> > > http://www.cs.unm.edu/~kmorel<http://www.cs.unm.edu/%7Ekmorel>
> > >
> > _______________________________________________
> > Powered by www.kitware.com
> >
> > Visit other Kitware open-source projects at
> > http://www.kitware.com/opensource/opensource.html
> >
> > Please keep messages on-topic and check the ParaView Wiki at:
> > http://paraview.org/Wiki/ParaView
> >
> > Follow this link to subscribe/unsubscribe:
> > http://www.paraview.org/mailman/listinfo/paraview
> >

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