Date: Wed, 30 May 2007 14:24:43 -0400 (EDT) From: Andrew Gallatin <gallatin@cs.duke.edu> To: security <security@jim-liesl.org> Cc: freebsd-performance@freebsd.org Subject: Re: [Fwd: asymetric speeds over gigE link] Message-ID: <18013.49538.356407.283631@grasshopper.cs.duke.edu> In-Reply-To: <4652383E.9000302@jim-liesl.org> References: <4652383E.9000302@jim-liesl.org>
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security writes: > Sent this to -net and didn't get much info, so I'll try here since > there's some overlap > > Summary: Using iperf to measure TCP net speed between a linux (kubuntu edgy) and Iperf is probably your problem, it tends to perform really poorly on nearly any OS other than linux as it measures lots of things besides network performance (like gettimeofday performance). Try a network benchmark that just benchmarks the network, like netperf. For example, on an amd64x2 running -current, I see ~4.75Gb/s from netperf (no options) and 2.85Gb/s from iperf (no options) Drew % netperf242 -H127.0.0.1 TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 127.0.0.1 (127.0.0.1) port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 65536 32768 32768 10.00 4757.03 % iperf -c 127.0.0.1 ------------------------------------------------------------ Client connecting to 127.0.0.1, TCP port 5001 TCP window size: 42.0 KByte (default) ------------------------------------------------------------ [ 3] local 127.0.0.1 port 60961 connected with 127.0.0.1 port 5001 [ 3] 0.0-10.0 sec 3.31 GBytes 2.85 Gbits/sec
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