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<div>Thanks for the update, Dan. If you can share your torus config file (and code, if you have made modifications), I can take a quick peek and may be able to help you out.</div>
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<span style="font-weight:bold">From: </span><<a href="mailto:codes-ross-users-bounces@lists.mcs.anl.gov">codes-ross-users-bounces@lists.mcs.anl.gov</a>> on behalf of Daniel Parker <<a href="mailto:dkparker@uchicago.edu">dkparker@uchicago.edu</a>><br>
<span style="font-weight:bold">Date: </span>Thursday, July 23, 2015 at 2:46 PM<br>
<span style="font-weight:bold">To: </span>"<a href="mailto:codes-ross-users@lists.mcs.anl.gov">codes-ross-users@lists.mcs.anl.gov</a>" <<a href="mailto:codes-ross-users@lists.mcs.anl.gov">codes-ross-users@lists.mcs.anl.gov</a>><br>
<span style="font-weight:bold">Subject: </span>[codes-ross-users] Correlation between latency and number of hops on torus network?<br>
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<div>Hello,<br>
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First I wanted to thank Jonathan and Misbah for their help on my last question. I was successful in setting up networks where arbitrary numbers of nodes are active or inactive.<br>
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Now that I am able to do so, however, I have made a strange observation. It seems to me that there is not a correlation between the number of hops that a message must make over a torus network and that message's latency. To determine this, I created a simple
model where one sender and one receiver node are randomly chosen within a 3D 10x10x10 torus network. I take latency measurements for 10 pings from the sender to the receiver and back, then average the values. I repeated this trial 500 times and aggregated
the data into these graphs:<br>
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<a href="http://imgur.com/a/7rqRw">http://imgur.com/a/7rqRw</a><br>
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The first graph shows a cdf of latencies of the different trials, with each data point color-coded corresponding to the number of hops between the sender and receiver for that trial. Blue indicates few hops while red indicates more. The second shows the distribution
of hop counts observed over the 500 trials, with number of hops on the x axis and frequency on the y axis. As you can see, the latency seems constant despite distance between the nodes in question, which does not make sense to me. Do any of you know why this
would be? Is there something about the torus implementation that I'm misunderstanding?<br>
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<div>I can upload my code if necessary.<br>
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Thanks for your help,<br>
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Dan Parker<br>
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