[lwip-users] lwIP RAW - Low throughput during first few seconds

[Nenad Pekez]

Hello everyone,

we have been measuring throughput between PC Windows 7 and Zynq device using iperf applications. For Windows 7, we use official iperf client application, while for our Zynq based board we have downloaded iperf lwIP RAW server implementation from Zynq manufacturer - Xilinx. We send data from PC to Zynq.

As expected, throughput is quite high, almost 1Gb, but only after first 4 to 5 seconds. During this few first seconds, data transfer is almost non-existent. Does anyone have idea what could be the cause of this? Is there any way to avoid this and have active data transfers all the time including this first few seconds? 

I was thinking that problem could be to iperf client, however, even with our basic client implementation, the behavior is the same.

In attachments I provide:

• iperf_throughput.png - screenshot of iperf measurements,
  
• lwipopts.h - our lwIP configuration file and
• rxperf.c - lwIP server implementation file.
  

If any additional information is needed, let me know.

Best regards,
Nenad

iperf_throughput.png
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lwipopts.h
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rxperf.c
Description: Text document