<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><div dir="ltr">Is the ethernet connection a single dedicated cable between the two machines or are you running through a switch that handles other traffic?<div><br></div><div>My best guess is that this is noise and that you may be able to avoid it by running a very long time, e.g. 10000 iterations.</div><div><br></div><div>Jeff</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jun 20, 2018 at 6:53 AM, Abu Naser <span dir="ltr"><<a href="mailto:an16e@my.fsu.edu" target="_blank">an16e@my.fsu.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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<p style="margin-top:0;margin-bottom:0">Good day to all,</p>
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<p style="margin-top:0;margin-bottom:0">I had run point to point osu_latency test in two nodes for 200 times. Followings are the average time in microsecond for various size of the messages -</p>
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<div>1KB 84.8514 us<br>
<span style="color:rgb(255,0,0)">2KB 73.52535</span> us<br>
4KB 272.55275 us<br>
<span style="color:rgb(255,0,0)">8KB 234.86385</span> us<br>
16KB 288.88 us<br>
32KB 523.3725 us<br>
64KB 910.4025 us</div>
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<p style="margin-top:0;margin-bottom:0">From the above looks like, 2KB message has less latency than 1 KB and 8KB has less latency than 4KB.
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<p style="margin-top:0;margin-bottom:0">I was looking for explanation of this behavior but did not get any.</p>
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<li><span>MPIR_CVAR_CH3_EAGER_MAX_MSG_<wbr>SIZE</span><span> is set to 128KB. So none of the above message size is using Rendezvous protocol. Is there any partition inside eager protocol (e.g. 0 - 512 bytes, 1KB - 8KB, 16KB - 64KB)? If yes then what are the boundaries
for them? Can I log them with debug-event-logging? </span><br>
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<p style="margin-top:0;margin-bottom:0">Setup I am using:</p>
<p style="margin-top:0;margin-bottom:0">- two nodes has intel core i7, one with 16gb memory another one 8gb</p>
<p style="margin-top:0;margin-bottom:0">- mpich 3.2.1, configured and build to use nemesis tcp</p>
<p style="margin-top:0;margin-bottom:0">- 1gb Ethernet connection</p>
<p style="margin-top:0;margin-bottom:0">- NFS is using for sharing<br>
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<p style="margin-top:0;margin-bottom:0">- osu_latency : uses MPI_Send and MPI_Recv</p>
<p style="margin-top:0;margin-bottom:0">- <span>MPIR_CVAR_CH3_EAGER_MAX_MSG_<wbr>SIZE</span>=
<span>131072</span> (128KB)<br>
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<p style="margin-top:0;margin-bottom:0">Can anyone help me on that? Thanks in advance.<br>
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<p align="left"><span style="font-size:10pt;font-family:Calibri,Helvetica,sans-serif">Best Regards,</span></p>
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<p align="left"><span style="font-size:10pt;font-family:Calibri,Helvetica,sans-serif">Abu Naser</span><br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature">Jeff Hammond<br><a href="mailto:jeff.science@gmail.com" target="_blank">jeff.science@gmail.com</a><br><a href="http://jeffhammond.github.io/" target="_blank">http://jeffhammond.github.io/</a></div>
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