Dear Feng,<div><br></div><div>Normally the efficiency of the cluster will go down if you increase the number of processors. However there will be improvement when you increase the processors. If the efficiency of the 8 processors is less than two then it is your network card. If you have InfiniBand you will get good performance but costly affair. If you have gigabit connectivity then what you experience will happen. Depending on budget you have you can go for 10 gig or 40 gig connectivity to improve the efficiency.</div>
<div><br></div><div><br></div><div><div class="gmail_quote">On Wed, Nov 17, 2010 at 12:30 AM, <span dir="ltr"><<a href="mailto:wrf-users-request@ucar.edu">wrf-users-request@ucar.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
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Today's Topics:<br>
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1. The efficiency problem to run WRFV3.2.1 on a cluster with 8<br>
nodes (Feng Liu)<br>
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Message: 1<br>
Date: Fri, 12 Nov 2010 21:35:55 +0000<br>
From: Feng Liu <<a href="mailto:FLiu@azmag.gov">FLiu@azmag.gov</a>><br>
Subject: [Wrf-users] The efficiency problem to run WRFV3.2.1 on a<br>
cluster with 8 nodes<br>
To: "<a href="mailto:wrf-users@ucar.edu">wrf-users@ucar.edu</a>" <<a href="mailto:wrf-users@ucar.edu">wrf-users@ucar.edu</a>><br>
Cc: wrfhelp <<a href="mailto:wrfhelp@ucar.edu">wrfhelp@ucar.edu</a>>, Feng Liu <<a href="mailto:FLiu@azmag.gov">FLiu@azmag.gov</a>><br>
Message-ID: <9BDE2A7F9712AF45A0C08451B3CD8E5C029AEF37@mag9006><br>
Content-Type: text/plain; charset="us-ascii"<br>
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Hi, there,<br>
I'm trying to run WRF model with parallelized version with 2, 4, 8, or 16 processors on a Linux cluster with 8 nodes (each node is formed by 2-quadcores). Runs got slower with increasing the number of processors (np)! It runs correctly on all nodes but so slow. When I switch to np=2, model is running on the master node only and faster. The overall time of the simulation is bigger than for the single node run... Is the problem associated with bandwidth? network card? I have no idea. Anyone have experienced the same problem? Thanks.<br>
Feng<br>
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End of Wrf-users Digest, Vol 75, Issue 7<br>
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