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<DIV>Good day list!</DIV>
<DIV> I'm having a problem with netem that is taking me hours to try and diagnose what the problem is. I think I finally have it narrowed down to something in netem or on our netem machine.</DIV>
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<DIV>First the background.</DIV>
<DIV> </DIV>
<DIV>We seem to be having the same problem that a chap did back in January (<A href="https://lists.linux-foundation.org/pipermail/netem/2007-January/001059.html" target=_blank rel=nofollow><FONT color=#810081>https://lists.linux-foundation.org/pipermail/netem/2007-January/001059.html</FONT></A>) whereby introducing a delay of any kind with netem seems to kill UDP throughput using iperf. At 150ms, it pretty consistently seems to be gated down to around 150Mbps.</DIV>
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<DIV>Now, I've done some runs (not repeatable) that are around the 600Mbps range on the same hardware and same netem settings but they are very sporadic (say 1 in 50 tests). I also know from real world testing that iperf can easily push 900Mbps at 150Mbps on a gigabit connection so...</DIV>
<DIV> </DIV>
<DIV>what gives? I've tried all kinds of limit settings on netem, checked for packet loss, buffer sizing all to no avail. Still, the magic 150Mbps rate keeps showing up.</DIV>
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<DIV>The last option is to try the 2.6.22 kernel in the hopes that this is timer related. But that is going to be major for me as we currently run RHEL 5 on the netem machine and there is no .22 kernel from RH yet.</DIV>
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<DIV>Any obvious things I'm missing? I think I've gained 1 or 2 grey hairs!</DIV>
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<DIV>Thanks</DIV>
<DIV><BR>Dave</DIV></DIV></DIV></div><br>
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