No subject
Mon Aug 10 18:29:21 EDT 2009
<BR>
</FONT></SPAN></FONT><BLOCKQUOTE><FONT SIZE=3D"2"><SPAN STYLE=3D'font-size:=
10pt'><FONT FACE=3D"Tahoma, Verdana, Helvetica, Arial"><BR>
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, w=
hich makes me wonder why the time (still render) decrease initially but inc=
rease 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 GH=
z)<BR>
</FONT><FONT FACE=3D"Verdana, Helvetica, Arial"><BR>
</FONT></SPAN></FONT></BLOCKQUOTE><FONT SIZE=3D"2"><SPAN STYLE=3D'font-size=
:10pt'><FONT FACE=3D"Verdana, Helvetica, Arial"><BR>
ParaView doesn't use parallelism to scale in terms of processing speed, it =
uses it to scale in terms of achievable data size. That means, if you have =
sufficient memory on one machine, processing the data on two machines isn't=
likely to give you any speed up and will usually slow it down because of t=
he extra code and especially communication that has to happen in the parall=
el program (Ahmdahls law). If the problem is too big for one machine, then =
the only alternative is to split the data and run it on many machines (Gust=
afsen's law). That said, if the data is nearly to big for one machine, for =
instance when swapping, then splitting it and running it on several machine=
s will make it faster for a while until the overhead starts to dominate the=
performance.<BR>
<BR>
<BR>
</FONT></SPAN></FONT><BLOCKQUOTE><FONT SIZE=3D"2"><SPAN STYLE=3D'font-size:=
10pt'><FONT FACE=3D"Tahoma, Verdana, Helvetica, Arial"><BR>
----------------------------------------------<BR>
</FONT><FONT FACE=3D"Verdana, Helvetica, Arial">number of process used stil=
l render (seconds) <BR>
np1 7.16043 <BR>
np2 3.93390 <BR>
np3 3.05784 <BR>
np4 3.02900 <BR>
np5 3.02851 <BR>
np6 3.04962 <BR>
np7 3.43479 <BR>
np8 3.47883 <BR>
np9 3.71554 <BR>
np10 3.80835<BR>
</FONT><FONT FACE=3D"Tahoma, Verdana, Helvetica, Arial">-------------------=
---------------------------<BR>
<BR>
<BR>
appreciate your reply!<BR>
<BR>
regards,<BR>
chewping<BR>
<BR>
<BR>
</FONT><FONT FACE=3D"Verdana, Helvetica, Arial"><HR ALIGN=3DCENTER SIZE=3D"=
3" WIDTH=3D"100%">From: <a href=3D"kmorel at sandia.gov">kmorel at sandia.gov</a>=
<BR>
To: <a href=3D"lcp81um at msn.com">lcp81um at msn.com</a>; <a href=3D"paraview at pa=
raview.org">paraview at paraview.org</a><BR>
CC: <a href=3D"kitware at kitware.com">kitware at kitware.com</a><BR>
Date: Mon, 28 Sep 2009 08:37:08 -0600<BR>
Subject: Re: [Paraview] How to interpret timer log <BR>
<BR>
<BR>
</FONT></SPAN></FONT><FONT FACE=3D"Calibri, Verdana, Helvetica, Arial"><SPA=
N STYLE=3D'font-size:11pt'>Both scenarios are wrong. ParaView will no=
t 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 n=
o such reader). What is actually happening is more along the lines of=
:<BR>
<BR>
</SPAN></FONT><OL><LI><FONT FACE=3D"Calibri, Verdana, Helvetica, Arial"><SP=
AN STYLE=3D'font-size:11pt'>Processes 0-3 each read in a partition of data =
from the file.=20
</SPAN></FONT><LI><FONT FACE=3D"Calibri, Verdana, Helvetica, Arial"><SPAN S=
TYLE=3D'font-size:11pt'>Each process extracts polygonal geometry from their=
local data.=20
</SPAN></FONT><LI><FONT FACE=3D"Calibri, Verdana, Helvetica, Arial"><SPAN S=
TYLE=3D'font-size:11pt'>Per your settings, ParaView decides to send the geo=
metry to the client. The data is collected to process 0 and sent to t=
he client.<BR>
</SPAN></FONT></OL><FONT FACE=3D"Calibri, Verdana, Helvetica, Arial"><SPAN =
STYLE=3D'font-size:11pt'><BR>
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 execut=
es under a certain amount of time (by default 0.01 seconds). If you c=
hange the Time Threshold to Show All, you should be able to see everything =
that executes, even if it completes immediately.<BR>
<BR>
You should note that how readers read partitions is determined by the reade=
r itself. Many of the readers do not really handle partitioned readin=
g. Thus, the reader will do something naïve like read everything=
on process 0. Based on your timings, that is probably what is happen=
ing to you. That is, processes 1-3 probably have empty data. Yo=
u never specified what format of data you are reader, so I cannot answer th=
e data completely. However, if you want to know how your data is part=
itioned on the server (at least, before rendering), you can run the Process=
Ids filter.<BR>
<BR>
-Ken<BR>
<BR>
<BR>
On 9/24/09 9:09 PM, "chew ping" <<a href=3D"lcp81um at msn.com">l=
cp81um at msn.com</a> <<a href=3D"http://msn.com/">http://msn.com/</a>> =
> wrote:<BR>
<BR>
</SPAN></FONT><BLOCKQUOTE><FONT SIZE=3D"2"><FONT FACE=3D"Verdana, Helvetica=
, Arial"><SPAN STYLE=3D'font-size:10pt'>Hi all,<BR>
<BR>
I'm doing parallel rendering using 1 client (dual core laptop) and 2 cluste=
r servers (dual core desktop)<BR>
below is the timer log result i collected when i run: mpirun -np 4 pvserver=
<BR>
<BR>
---------------------------------------------------------------------------=
--------------------<BR>
</SPAN></FONT><SPAN STYLE=3D'font-size:10pt'><FONT FACE=3D"Tahoma, Verdana,=
Helvetica, Arial">Local Process<BR>
Still Render, 3.029 seconds<BR>
Execute vtkMPIMoveData id: 457, 1.98248 seconds<BR>
<BR>
<BR>
Server, Process 0<BR>
Execute vtkFileSeriesReader id: 176, 0.637821 seconds<BR>
Execute vtkMPIMoveData id: 457, 1.49186 seconds<BR>
Dataserver gathering to 0, 0.829525 seconds<BR>
Dataserver sending to client, 0.661658 seconds<BR>
</FONT><FONT FACE=3D"Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE=3D"Tahoma, Verdana, Helvetica, Arial">Server, Process 1<B=
R>
Execute vtkMPIMoveData id: 457, 0.141821 seconds<BR>
Dataserver gathering to 0, 0.141544 seconds<BR>
</FONT><FONT FACE=3D"Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE=3D"Tahoma, Verdana, Helvetica, Arial">Server, Process 2<B=
R>
Execute vtkMPIMoveData id: 457, 0.243584 seconds<BR>
Dataserver gathering to 0, 0.243318 seconds<BR>
</FONT><FONT FACE=3D"Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE=3D"Tahoma, Verdana, Helvetica, Arial">Server, Process 3<B=
R>
Execute vtkMPIMoveData id: 457, 0.191589 seconds<BR>
Dataserver gathering to 0, 0.191303 seconds<BR>
</FONT><FONT FACE=3D"Verdana, Helvetica, Arial"><BR>
---------------------------------------------------------------------------=
--------------------------<BR>
<BR>
i have difficulty interpreting the timer log, my guess is:<BR>
<BR>
Scenario 1: <BR>
Process 0 reads the whole data, disseminate the dats into 4 pieces, then di=
stribute to itself and Process 1&2&3,<BR>
each node will process the data and send it back Process 0,<BR>
Process 0 gather all data and send it back to client,<BR>
client renders the data<BR>
<BR>
Scenario 2:<BR>
Process 0 reads the whole data, distribute the whole data to Process 0&=
1&2&3,<BR>
each node will 'take' their own piece of data to process, then send it back=
Process 0,<BR>
Process 0 gather all data and send it back to client,<BR>
client renders the data<BR>
<BR>
Which scenario is the correct one? or both are wrong?<BR>
<BR>
is there any resources i could refer to find what does it mean by: Execute =
vtkFileSeriesReader, Execute vtkMPIMoveData?<BR>
<BR>
any help / feedback is highly appreciated!<BR>
thanks!<BR>
<BR>
regards,<BR>
chewping<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
</FONT></SPAN></FONT></BLOCKQUOTE><FONT SIZE=3D"2"><SPAN STYLE=3D'font-size=
:10pt'><FONT FACE=3D"Verdana, Helvetica, Arial"><BR>
</FONT><FONT FACE=3D"Consolas, Courier New, Courier"><BR>
**** Kenneth Moreland<BR>
*** Sandia National L=
aboratories<BR>
*********** <BR>
*** *** *** email: <a href=3D"kmorel at sandia.gov">kmorel at sandia.gov</a=
> <<a href=3D"http://sandia.gov/">http://sandia.gov/</a>> <BR>
** *** ** phone: (505) 844-8919<BR>
*** web: =
<a href=3D"http://www.cs.unm.edu/~kmorel">http://www.cs.unm.edu/~kmorel</a>=
<BR>
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**** Kenneth Moreland<BR>
*** Sandia National L=
aboratories<BR>
*********** <BR>
*** *** *** email: <a href=3D"kmorel at sandia.gov">kmorel at sandia.gov</a=
><BR>
** *** ** phone: (505) 844-8919<BR>
*** web: =
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