UDP packet loss

[ismail fatih iltar]

Posted on July 02, 2018 at 13:38

Hi, im using stm32f7+ freertos+lwip (raw api). My system handles web server and udp data communication. My frame length is 572 bytes and my FPS is 40 (22880 bytes/sec) at start. When i increase the package number to 8 times (8*572*40 = 183040 bytes/sec) it drops a lots of udp packages.(Especially dropping starts after 6 times = 6*572*40=137kbits) The weird thing is: if i decrease it to 22880 bytes/sec again it cant returns the normal situation it still drops. I have to reset for normal again. Im not expert lwip so i think there is a problem about buffers. I need an advice.

#ethernet #stm32f7 #lwip #udp #freertos

[Gavin Baker]

Posted on July 09, 2018 at 02:51

I have had some experience with LWIP, and in the past encountered similar performance problems with the default settings. The defaults are really all tuned to the most minimal settings, which suit systems with very meagre resources, but invariably limit performance on any reasonable processor.

As a rule, LWIP needs to be tuned for each system it is deployed on. And that extends to the interfacing with the MAC and PHY.

IMHO there is no reason to upgrade to a Cortex-A based on your problem description. You should be able to calculate a theoretical upper limit your M7 can handle to assess whether you are really limited by the processor.

[pushkin]

hi, ismail fatih iltar,

I have same problem, UDP packet loss... My frame length is 1482 bytes and my FPS is 25 (37050 bytes/sec).
board: stm32f767zi
Can you help me with tuning my lwip settings/buffers?