On Fri, 30 Apr 2010 13:51:26 -0500 "[email protected]" <[email protected]> wrote:
> Excerpts from Jimmy Shao's message of Fri Apr 30 13:31:23 -0500 2010: > > Hello, > > > > This is Jimmy. > > I am performing some iperf throughput test using 10 G and 1 G card. > > > > My set up as following: > > > > Server with 10G NIC---- (10G interface-SW ---1G interface)-----Client with > > 1G > > NIC > > > > The problem: > > > > The iperf test (TCP throughput) result only shows the throughput only can > > reach > > up to 500M, and when using IXIA I can get up to 1G. > > Is there any limitation in iperf for throughput test? > > How many traffic (throughput) iperf can generate? > > BTW, on switch I also turn off the" flow control" function. > > > > Any input and comments are welcome. > > Hi Jimmy, > > I'd expect you to be able to easily get 990 Mb/s with this configuration > assuming reasonable hardware for the test PCs (eg 1GHz or better). > > How long do you let the TCP test run? The autotuning (assuming you're running > a newish Linux) can take a little bit to set up, so I'd suggest running for a > few minutes rather than say just 30 seconds. > > Is there any cross traffic in your setup or is this the only traffic? > > What operating system and version is Iperf running on? Which version of > Iperf? Single threaded or multi threaded? > > I haven't looked at Ixia's product line in quite some time, but last time I > did they may have sent traffic that had TCP set in the protocol field of the > IP header, but it didn't actually implement the TCP machinery. In other words > it's blasting bits that say they're TCP but none of the TCP dynamics apply. > It's possible that newer Ixia gear actually runs a TCP machine, but I kind of > doubt it. > > Jon How much buffering is in the 10G - 1G point? TCP will have a hard time if switch doesn't have sufficient buffering. TCP will send packet trains and switch without buffering will end up dropping lots of frames. -- ------------------------------------------------------------------------------ _______________________________________________ Iperf-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/iperf-users
