Hi! I did some UDP tests and observed strange behaviors when using version 2.0.4 on certain Linux server. To avoid network/interface problems I did all the tests local via the loopback interface (127.0.0.1).
============================================================ = Debian sarge: 2.6.12.5 = ============================================================ Iperf 2.0.2: ./iperf -c 127.0.0.1 ------------------------------------------------------------ Client connecting to 127.0.0.1, TCP port 5001 TCP window size: 49.2 KByte (default) ------------------------------------------------------------ [ 3] local 127.0.0.1 port 38177 connected with 127.0.0.1 port 5001 [ 3] 0.0-10.0 sec 1.39 GBytes 1.20 Gbits/sec Iperf 2.0.2: ./iperf -c 127.0.0.1 -u -b 1000M ------------------------------------------------------------ Client connecting to 127.0.0.1, UDP port 5001 Sending 1470 byte datagrams UDP buffer size: 108 KByte (default) ------------------------------------------------------------ [ 3] local 127.0.0.1 port 39722 connected with 127.0.0.1 port 5001 [ 3] 0.0-10.0 sec 462 MBytes 387 Mbits/sec [ 3] Sent 329332 datagrams [ 3] Server Report: [ 3] 0.0-10.0 sec 462 MBytes 387 Mbits/sec 0.002 ms 0/329331 (0%) [ 3] 0.0-10.0 sec 1 datagrams received out-of-order IMO it is very strange that the UDP permformance is much lower then TCP, but so far so good, now doing the same tests with Iperf 2.0.4: Iperf 2.0.4: ./iperf -c 127.0.0.1 ------------------------------------------------------------ Client connecting to 127.0.0.1, TCP port 5001 TCP window size: 49.2 KByte (default) ------------------------------------------------------------ [ 3] local 127.0.0.1 port 38179 connected with 127.0.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 1.58 GBytes 1.36 Gbits/sec Iperf 2.0.4: ./iperf -c 127.0.0.1 -u -b 1000M ------------------------------------------------------------ Client connecting to 127.0.0.1, UDP port 5001 Sending 1470 byte datagrams UDP buffer size: 108 KByte (default) ------------------------------------------------------------ [ 3] local 127.0.0.1 port 39722 connected with 127.0.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.1 sec 35.4 MBytes 29.5 Mbits/sec [ 3] Sent 25269 datagrams [ 3] Server Report: [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 3] 0.0-10.1 sec 35.4 MBytes 29.5 Mbits/sec 0.003 ms 0/25268 (0%) [ 3] 0.0-10.1 sec 1 datagrams received out-of-order As you see, the UDP performance is now really poor. I observed the same behavior (UDP performance drop when using Iperf 2.0.4) on a debian etch box (2.6.8-2-386) and on a Centos5.1 box (2.6.18-92.1.6.el5). Only on an Ubuntu Box (2.6.24-19-generic) the UDP performance did not decreased when unsing Iperf 2.0.4). Any hints? thanks klaus ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Iperf-users mailing list Iperf-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/iperf-users
