Hi Marek There is an automatic back-off mechanism designed to stop nodes flooding the network with small TCP messages called Nagle algorithm. Check if you are being blocked by that. You can turn it off - i think on a per connection basis.
There is also a similar thread that I found when i was looking at a similar problem http://lwip.100.n7.nabble.com/lwIP-hangs-on-transfers-with-many-short-packets-td11044.html BR Simon ________________________________ From: lwip-users <lwip-users-bounces+simon.wilton=ability-it....@nongnu.org> on behalf of mjanicek <mjani...@cominfo.cz> Sent: 03 March 2020 08:46 To: lwip-users@nongnu.org <lwip-users@nongnu.org> Subject: [lwip-users] FreeRTOS + Lwip, transmit gets BLOCKED Hello, I have STM32F407 running FreeRTOS + Lwip (netconn). I have several tasks. Only one Task1 is transmitting continously small packets (85 bytes) every 5 miliseconds on ethernet. Transmitting is randomly paused for a long time (cca 1-2 sec) then it is resumed. Task1 in function lwip_netconn_do_write() takes the semaphore by sys_arch_sem_wait(LWIP_API_MSG_SEM(msg), 0) and Task1 gets BLOCKED. It remains blocked for cca 1-2 seconds. When tcpip_thread in function lwip_netconn_do_writemore() gives semaphore by sys_sem_signal(op_completed_sem) then Task1 gets finally READY. Please do you have idea why this is happening for such a long time? Thanks Marek -- Sent from: http://lwip.100.n7.nabble.com/lwip-users-f3.html _______________________________________________ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
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