<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">Yeah, I don't think the TCP buffers will affect UDP traffic :)</DIV>
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<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">D<BR><BR></DIV>
<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, times, serif">----- Original Message ----<BR>From: Lucas Nussbaum <lucas@lucas-nussbaum.net><BR>To: Dave North <dnorth98@yahoo.com><BR>Cc: netem@lists.linux-foundation.org<BR>Sent: Monday, November 12, 2007 7:01:20 PM<BR>Subject: Re: [Netem] netem / gigabit / 2.6.18 / throughput killer<BR><BR>On 12/11/07 at 14:38 -0800, Dave North wrote:<BR>> Good day list!<BR>> 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.<BR>> <BR>> First the background.<BR>> <BR>> 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>https://lists.linux-foundation.org/pipermail/netem/2007-January/001059.html</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.<BR><BR>Check your TCP buffer sizes<BR><A href="http://dsd.lbl.gov/TCP-tuning/" target=_blank>http://dsd.lbl.gov/TCP-tuning/</A><BR><BR>Does the situation improve if the latency is set to say 50ms or 100ms ?<BR>-- <BR>| Lucas Nussbaum<BR>| <A href="mailto:lucas@lucas-nussbaum.net" ymailto="mailto:lucas@lucas-nussbaum.net">lucas@lucas-nussbaum.net</A> <A href="http://www.lucas-nussbaum.net/" target=_blank>http://www.lucas-nussbaum.net/</A> |<BR>| jabber: <A href="mailto:lucas@nussbaum.fr" ymailto="mailto:lucas@nussbaum.fr">lucas@nussbaum.fr</A> GPG: 1024D/023B3F4F |<BR></DIV>
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