[Paraview] How to interpret timer log

Wed Sep 30 11:05:59 EDT 2009

The still render measures the time from when the render is initiated to the time when the render completes.  In client/server mode, this can include communication and parallel overhead costs.

ParaView has two types of renders: still render and interactive render.  Interactive renders occur while you are interacting with the 3D view by moving the mouse.  It tries to maintain interactive rendering rates.  Still renders happen after interaction stops to give a full resolution view of your data.

The vtkMPIMoveData filter is a special filter that collects poly data on the server and pushes it to the client.  ParaView settings determine when this happens.  Generally when the size of the data is below a certain threshold, then ParaView will push the data to the client.

-Ken

On 9/30/09 5:11 AM, "chew ping" <lcp81um at msn.com> wrote:

Dear Ken,

thanks for the reply. i have one more question to ask.
in the timer log, the first 3 lines:

--------------------------------------------------
Local Process
Still Render, 3.029 seconds
Execute vtkMPIMoveData id: 457, 1.98248 seconds
--------------------------------------------------

does these mean that, at the client's end, it took 3.029 seconds to renders the geometry send back from process 0?
what does still render means? how about the third line? after still render, why does the MPI need to move data? which data? to where?

i tried running the same data using np1 until np10, and i get the following reading for still render, the rest of the readings are quite consistent, which makes me wonder why the time (still render) decrease initially but increase eventually? shouldn't it become much faster when more nodes are used? all my server nodes are identical to each other (intel core 2 duo, 2.66 GHz)

----------------------------------------------
number of process used still render (seconds)
np1 7.16043
np2 3.93390
np3 3.05784
np4 3.02900
np5 3.02851
np6 3.04962
np7 3.43479
np8 3.47883
np9 3.71554
np10 3.80835
----------------------------------------------

appreciate your reply!

regards,
chewping

________________________________
From: kmorel at sandia.gov
To: lcp81um at msn.com; paraview at paraview.org
CC: kitware at kitware.com
Date: Mon, 28 Sep 2009 08:37:08 -0600
Subject: Re: [Paraview] How to interpret timer log

Re: [Paraview] How to interpret timer log Both scenarios are wrong.  ParaView will not push out data from process 0 to processes 1-3 unless you explicitly run a filter that does that (or the reader does that internally, but I know of no such reader).  What is actually happening is more along the lines of:

 1.  Processes 0-3 each read in a partition of data from the file.
 2.  Each process extracts polygonal geometry from their local data.
 3.  Per your settings, ParaView decides to send the geometry to the client.  The data is collected to process 0 and sent to the client.

The reason you are not seeing vtkFileSeriesReader on all of the servers is that there is a threshold in the timer log to not show anything that executes under a certain amount of time (by default 0.01 seconds).  If you change the Time Threshold to Show All, you should be able to see everything that executes, even if it completes immediately.

You should note that how readers read partitions is determined by the reader itself.  Many of the readers do not really handle partitioned reading.  Thus, the reader will do something naïve like read everything on process 0.  Based on your timings, that is probably what is happening to you.  That is, processes 1-3 probably have empty data.  You never specified what format of data you are reader, so I cannot answer the data completely.  However, if you want to know how your data is partitioned on the server (at least, before rendering), you can run the Process Ids filter.

-Ken

On 9/24/09 9:09 PM, "chew ping" <lcp81um at msn.com <http://msn.com> > wrote:

Hi all,

I'm doing parallel rendering using 1 client (dual core laptop) and 2 cluster servers (dual core desktop)
below is the timer log result i collected when i run: mpirun -np 4 pvserver

-----------------------------------------------------------------------------------------------
Local Process
Still Render, 3.029 seconds
Execute vtkMPIMoveData id: 457, 1.98248 seconds

Server, Process 0
Execute vtkFileSeriesReader id: 176, 0.637821 seconds
Execute vtkMPIMoveData id: 457, 1.49186 seconds
Dataserver gathering to 0, 0.829525 seconds
Dataserver sending to client, 0.661658 seconds

Server, Process 1
Execute vtkMPIMoveData id: 457, 0.141821 seconds
Dataserver gathering to 0, 0.141544 seconds

Server, Process 2
Execute vtkMPIMoveData id: 457, 0.243584 seconds
Dataserver gathering to 0, 0.243318 seconds

Server, Process 3
Execute vtkMPIMoveData id: 457, 0.191589 seconds
Dataserver gathering to 0, 0.191303 seconds

-----------------------------------------------------------------------------------------------------

i have difficulty interpreting the timer log, my guess is:

Scenario 1:
Process 0 reads the whole data, disseminate the dats into 4 pieces, then distribute to itself and Process 1&2&3,
each node will process the data and send it back Process 0,
Process 0 gather all data and send it back to client,
client renders the data

Scenario 2:
Process 0 reads the whole data, distribute the whole data to Process 0&1&2&3,
each node will 'take' their own piece of data to process, then send it back Process 0,
Process 0 gather all data and send it back to client,
client renders the data

Which scenario is the correct one? or both are wrong?

is there any resources i could refer to find what does it mean by: Execute vtkFileSeriesReader, Execute vtkMPIMoveData?

any help / feedback is highly appreciated!
thanks!

regards,
chewping

   ****      Kenneth Moreland
    ***      Sandia National Laboratories
***********
*** *** ***  email: kmorel at sandia.gov <http://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

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