perfSONAR User Q&A and Other Discussion

[Brian Tierney <>]

Some other things to check:

does owping show packet loss?

does iperf3 should TCP retransmits?

If so, then you likely have congestion or bad connections on that path.

see: https://fasterdata.es.net/performance-testing/troubleshooting/network-troubleshooting-quick-reference-guide/

You might also want to capture a tcpdump to look at what TCP is doing in detail:

https://fasterdata.es.net/performance-testing/network-troubleshooting-tools/tcpdump-tcptrace/

On Wed, Jan 27, 2016 at 5:53 AM, Rittenhouse, Robert (LACA) <> wrote:

I will look into the host tuning more. I just didn't want to lock myself out of the testpoint gear and have to take a nice, long, relaxing drive away from the office to fix it ;) 

I was able to run a bwctl command that when I told it to use iperf3 and to run 20 parallel processes and that got us up to 288Mbps. I just know with some of our time warner links, when we test, we seem to be limited to how big each flow can be. When we test back to our same iperf gear here (and the other way around) on some of our Time Warner fiber circuits, they always let a single stream go to it's full potential. I will surely try these host tuning settings and get back with you. It's rather frustrating when link testing...

Thank you,

Robert Rittenhouse
Network Coordinator
Licking Area Computer Association (LACA)
(740) 345-3400 ext. 220

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From: [] on behalf of Szymon Trocha []
Sent: Wednesday, January 27, 2016 3:47 AM
To: Rittenhouse, Robert (LACA)
Cc:
Subject: Re: [perfsonar-user] Forcing parallel flows for Throughput test

W dniu 26.01.2016 o 19:01, Rittenhouse, Robert (LACA) pisze:

I have a Perfsonar Centos Toolkit server set up as a central manager for (hopefully) automating our throughput and latency testing that we only do reactively.

My issue is, when I add a standard TCP throughput test to a remote Ubuntu perfsonar-testpoint machine, it's only able to pull about 25Mbps max for a single stream. There is a point-to-point fiber link between my building where the Central test server is and where the testpoint resides. We had this issue with iperf and we had to have it use a lot of processes to try and max the link out. It is a 500 Mbps link if that helps.

How would I accomplish this task with perfsonar and keep it automated?

Hi Robert,

There are many factors which may limit your throughput. Are there any network segments and network devices between the two systems? Is there any concurrent traffic on the links between the two systems?
Did you look at http://docs.perfsonar.net/manage_tuning.html for host tuning?

Regards,

-- 
Szymon Trocha

Poznań Supercomputing & Netw. Center ::: NETWORK OPERATION CENTER
Tel. +48 618582022 ::: http://noc.man.poznan.pl

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--

Brian Tierney, http://www.es.net/tierney
Energy Sciences Network (ESnet), Berkeley National Lab
http://fasterdata.es.net