Out of curiosity, is there any threading regardless of the -P? Iperf 2
create threads for traffic (client/server), the reporter and the listener.
I think that helps some even for a single traffic flow, i.e. multiple
clients suggested. (Also note: I tried assigning threads to cores using
cpu affinities but found the OS scheduling did a better job of things.)
Bob
On Fri, Jun 3, 2016 at 9:37 AM, Jon Dugan <jdu...@x1024.net> wrote:
> The reason for this performance differences is that iperf3 is single
> threaded, so all parallel streams will use a single core. At 40G you will
> be core limited
>
> To test 40G with iperf3, I do the following:
>
> Start 3 servers:
> iperf3 -s -p 5101
> iperf3 -s -p 5102
> iperf3 -s -p 5103
>
> and then run 3 clients, using the "-T" flag to label the output:
> iperf3 -c hostname -T s1 -p 5101 &; iperf3 -c hostname -T s2 -p 5102 &;
> iperf3 -c hostname -T s3 -p 5103 &;
>
> We have also updated the Fasterdata website:
>
>
> https://fasterdata.es.net/performance-testing/network-troubleshooting-tools/iperf-and-iperf3/iperf3-at-speeds-about-10gbps
>
> The Github issue has also been updated.
>
> Cheers,
>
> Jon
>
> On Thu, Jun 2, 2016 at 3:19 PM, Jeffrey Lane <jeffrey.l...@canonical.com>
> wrote:
>
>> 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
>> Iperf-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/iperf-users
>>
>
>
>
> ------------------------------------------------------------------------------
> 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
> Iperf-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/iperf-users
>
>
------------------------------------------------------------------------------
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
Iperf-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/iperf-users
