On Fri, Jun 3, 2016 at 12:47 PM, Bob McMahon <bob.mcma...@broadcom.com>
wrote:
> Out of curiosity, is there any threading regardless of the -P?
>
Nope, just 1 thread.
> 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
>
>
--
Brian Tierney, http://www.es.net/tierney
Energy Sciences Network (ESnet), Berkeley National Lab
http://fasterdata.es.net
------------------------------------------------------------------------------
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
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