[Paraview-developers] How does ParaView schedule render tasks among all the processes?

[Jie Chen]

sorry, forget to send to maillist

---------- Forwarded message ----------
From: Jie Chen <chenjie.hust at gmail.com>
Date: Tue, Feb 14, 2012 at 1:04 PM
Subject: Re: [Paraview-developers] How does ParaView schedule render tasks
among all the processes?
To: "Biddiscombe, John A." <biddisco at cscs.ch>


John,

Thanks for your answer. It's much clear to understand how ParaView splits a
file for parallel processing. However, I still have questions about merging
the split pieces into a final result:

1)How does ParaView merge the split pieces together after the pieces have
been processed by their pipelines?

2)Does the mergence occur in the server-side or the client-side?

3)Which function call would trigger this mergence? Just give me some clue,
I can find myself.

Thanks.

Jie


On Tue, Feb 14, 2012 at 11:43 AM, Biddiscombe, John A. <biddisco at cscs.ch>wrote:

>  Jie****
>
> ** **
>
> **1)      **each reader/source must split pieces itself. If I am a
> vtkSTUFFreader, when I execute, I am given a piece number or an extent
> (depending on datatype), based on this information, I read the part of the
> data that I was told to (the reader has to work out how to get the piece it
> was asked for)****
>
> **2)      **The number of pieces is currently always the same as the
> number of MPI ranks (but it doesn’t have to be). A reader can set
> MAX_PIECES to -1 initially before the description in 1) above happens,
> which tells the pipeline that it is allowed to split the data into as many
> pieces as it wants. Be careful that the pipeline also uses pieces to
> represent streaming data pieces, which is confusing, I am not considering
> this case here. data paralle pieces are not quite the same as streaming
> pieces. we’re talking data parallel now.****
>
> **3)      **assignment of piece number is essentially MPI rank****
>
> Hope this helps****
>
> ** **
>
> JB****
>
> ** **
>
> *From:* paraview-developers-bounces at paraview.org [mailto:
> paraview-developers-bounces at paraview.org] *On Behalf Of *Jie Chen
> *Sent:* 14 February 2012 17:38
> *To:* paraview-developers at paraview.org
> *Subject:* [Paraview-developers] How does ParaView schedule render tasks
> among all the processes?****
>
> ** **
>
>
> ****
>
> Hi all,****
>
> ** **
>
> I have installed the ParaView-3.12.0 on a cluster with MPI enabled. And I
> use it in a client-server mode.(pvserver is running on the cluster)****
>
> ** **
>
> I'm curious about how ParaView process a task parallelly. The following is
> my questions:****
>
> (1) How does ParaView split a file into multi-pieces for parallel
> processing, and how to combine the results together?  Is there any special
> process which handles these splitting and combining works?****
>
> ** **
>
> (2) What policy does ParaView use when it computes the number of pieces? *
> ***
>
> ** **
>
> (3)What policy does ParaView use when it assign the pieces to all the
> processes?****
>
> ** **
>
> I'm just beginning to look into the ParaView source code. Hope somebody
> can give me some clue.****
>
> ** **
>
> Thanks****
>
> ** **
>
> Jie****
>
> **
>




-- 
Jie Chen
Visiting Scholar
Department of EECS, University of Central Florida,
4000 Central Florida Blvd, Bld. 116 Rm. 231
Orlando, FL 32816, USA
Phone: 407-408-8917
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