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Visitor ilias
Registered: ‎05-14-2018

Low bandwidth in xapp1305 fror zcu102

Hi All,



I am testing 10Gb Ethernet  using binaries from xapp1305 ( Version: 1.2 from  19APR2018 )

My setup is

zcu102 FPGA with SFP+ adapter from Avago  connected to Intel 10Gb card on desktop Linux system.


I am running iperf3  on FPGA side 

iperf3 -c -b10G -w32M -t=99999 

and on PC side

iperf3 -s -i1

I am getting very low bandwidth of about 200Mb ( mega bit! not byte)


What is a really interesting , if i am adding -Z flag to iperf, I am getting a pretty good  bandwidth of about 1.8Gb ( giga bit)


It is very unusual that zero copy can make a x8 impact on network bandwidth.

Looking into wireshark capture, I see that in case of normal( non zero copy) session, TCP packet size is small( ~4K) which explains low bandwidth.


I will really appreciate a hint here, as moving our app to zero copy seems not simple

( actually, I am not sure how to do it from Linux user mode )











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Observer jbeck695
Registered: ‎05-22-2018

Re: Low bandwidth in xapp1305 fror zcu102

I'm curious if you ever figured out a solution here. It took me a while to finally get it working but I just got same connection you mention above working yesterday. My first performance test was to try iperf3 that was included in xapp1305 but iperf3 on zcu board was missing a library so I just ran a simple scp of an 8gb file. Throughput was awful (12M/sec) but I haven't really dug much as of yet. I'm doing that now & came across your post. I figured I'd reach out to see if you discovered any optimizations.



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Visitor ilias
Registered: ‎05-14-2018

Re: Low bandwidth in xapp1305 fror zcu102

It was some time ago, but I remember that upfarding xapp1305 reference design to v.1.3 ( https://www.xilinx.com/support/documentation/application_notes/xapp1305-ps-pl-based-ethernet-solution.pdf ) had a great impactr on the bandwidth.

Also, you may want to configure mtu to somethink like 9000

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