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Talpey, Thomas wrote:<br>
<blockquote cite="mid7.0.1.0.2.20060605114203.043ad738@netapp.com"
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<pre wrap="">At 11:38 AM 6/5/2006, hbchen wrote:
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<pre wrap="">Even with this IB-4X = 8Gb/sec = 1024 MB/sec the IPoIB bandwidth utilization is still very low.
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<pre wrap="">IPoIB=420MB/sec
bandwidth utilization= 420/1024 = 41.01%
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<pre wrap=""><!---->
Helen, have you measured the CPU utilizations during these runs?
Perhaps you are out of CPU.
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Tom,<br>
I am HB Chen from LANL not the Helen Chen from SNL.<br>
I didn't run out of CPU. It is about 70-80 % of CPU utilization.<br>
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<blockquote cite="mid7.0.1.0.2.20060605114203.043ad738@netapp.com"
type="cite">
<pre wrap="">Outrageous opinion follows.
Frankly, an IB HCA running Ethernet emulation is approximately the
world's worst 10GbE adapter (not to put too fine of a point on it :-) )
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The IP over Myrinet ( Ethernet emulation) can reach upto 96%-98%
bandwidth utilization why not the IPoIB ?<br>
<br>
HB Chen <br>
<a class="moz-txt-link-abbreviated" href="mailto:hbchen@lanl.gov">hbchen@lanl.gov</a><br>
<blockquote cite="mid7.0.1.0.2.20060605114203.043ad738@netapp.com"
type="cite">
<pre wrap="">There is no hardware checksumming, nor large-send offloading, both
of which force overhead onto software. And, as you just discovered
it isn't even 10Gb!
In general, network emulation layers are always going to perform more
poorly than native implementations. But this is only a generality learned
from years of experience with them.
Tom.
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