[Paraview] Paraview and Multicore

Thu May 13 20:48:11 EDT 2010

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 I have done similar processing on an other PC (an outdated one)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>
> >
> _______________________________________________
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>
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