Am 17.09.2021 um 10:34 schrieb Tomas Mudrunka: > Recently there was somebody reporting simillar issue and it turned out > that some (or most?) browsers use several concurent TCP/HTTP connections > to load single webpage. Number of these connections was bigger than > LWIPs default maximum number of concurent TCP connections, so you might > try to increase that as well...
That's true, but the 10 connections configured below should be enough I think. Anyway, if he's reading the pcap and seeing delays due to delayed ACK, new connections are probably not the problem. Having access to a trace of this might help, though! Regeards, Simon > > Tom > > > Dne 2021-09-16 08:49, Marco Giammarini napsal: >> Dear Simon, >> Thanks for your reply. >> I have set 40kB of heap, and every time I stop the microcontroller in >> debug mode during web site request, the free memory is over 70%. >> This is my configuration: >> >> #DEFINE MEM_SIZE (40*1024) >> >> #DEFINE MEMP_NUM_PBUF 28 >> >> #DEFINE MEMP_NUM_TCP_PCB 10 >> >> #DEFINE MEMP_NUM_TCP_PCB_LISTEN 3 >> >> #DEFINE MEMP_NUM_TCP_SEG 40 >> >> #DEFINE PBUF_POOL_SIZE 15 >> >> #DEFINE TCP_MSS (1500 - 40) >> >> #DEFINE TCP_SND_BUF (3*TCP_MSS) >> >> #DEFINE TCP_SND_QUEUELEN (6 * TCP_SND_BUF)/TCP_MSS >> >> #DEFINE TCP_WND (3*TCP_MSS) >> >> Is there anything I can change? >> >> Regards, >> Marco >> >>> Il giorno 15 set 2021, alle ore 09:55, goldsi...@gmx.de ha scritto: >>> >>> Am 15.09.2021 um 08:55 schrieb Marco Giammarini: >>> >>>> Dear All, >>>> I’m studying this problem more in-depth (with Wireshark), and I >>>> found >>>> that sometimes Windows reply with ACK after 40ms at every packet. >>>> In >>>> this case, with a file of 800kB, a packet of 1460B, we have more >>>> or less >>>> 500 packets, that multiplied for 40ms reach 20 seconds each file. >>>> I found that this problem is very common for Windows PC: >>>> * >>>> https://developpaper.com/lets-talk-about-the-magical-40-ms-of-tcp/ >>>> >>> <https://developpaper.com/lets-talk-about-the-magical-40-ms-of-tcp/> >>>> * >>>> >>> >> https://docs.microsoft.com/it-it/troubleshoot/windows-server/networking/registry-entry-control-tcp-acknowledgment-behavior >>>> >>> >> <https://docs.microsoft.com/it-it/troubleshoot/windows-server/networking/registry-entry-control-tcp-acknowledgment-behavior> >>>> >>>> Is there any way to solve the problem (or a workaround) by modify >>>> some >>>> parameters of lwIP? >>> >>> You should not have a speed problem even if the ACKs get delayed >>> further. Having a problem here suggests that your lwIP (memory) >>> options >>> limit the send window in such amount that transmission stalls until >>> the >>> next ACK is received. >>> >>> Unless you're really short on memory, you should probably review >>> your >>> TCP and memory related options in lwipopts.h >>> >>> Regards, >>> Simon >>> >>> _______________________________________________ >>> lwip-users mailing list >>> lwip-users@nongnu.org >>> https://lists.nongnu.org/mailman/listinfo/lwip-users >> _______________________________________________ >> lwip-users mailing list >> lwip-users@nongnu.org >> https://lists.nongnu.org/mailman/listinfo/lwip-users > _______________________________________________ lwip-users mailing list lwip-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/lwip-users
