I am running into a problem where there is a remarkable difference in reported throughput when using iperf2 vs iperf3.
With iperf2, and about 16 - 20 threads, I can get, reliably, between 32 and 35 Gb/s on a 40Gb segment. with iperf3 on exactly the same hardware, I only get 4Gb/s, sometimes I can get up to 11Gb/s. Is there some trick to getting more accurate results out of iperf3? There is nothing special about the network, in fact, the network consists of two servers with 40Gb cards connected directly, no intervening switch. There is no routing issue that I can find, the 40Gb ports are on a completely different address space than the onboard 1Gb ports, AND the 1Gb ports on each server can't talk to each other. Physically the ONLY way these servers can talk to each other is across the 40Gb link. Another person opened a bug for this: https://github.com/esnet/iperf/issues/408 and there are now three people on that thread reporting the same issues. Any suggestions for how to debug or resolve this? -- "Entropy isn't what it used to be." Jeff Lane - Server Certification Lead, Warrior Poet, Biker, Lover of Pie Phone: 919-442-8649 Ubuntu Ham: W4KDH Freenode IRC: bladernr or bladernr_ gpg: 1024D/3A14B2DD 8C88 B076 0DD7 B404 1417 C466 4ABD 3635 3A14 B2DD ------------------------------------------------------------------------------ What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic patterns at an interface-level. Reveals which users, apps, and protocols are consuming the most bandwidth. Provides multi-vendor support for NetFlow, J-Flow, sFlow and other flows. Make informed decisions using capacity planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e _______________________________________________ Iperf-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/iperf-users
