Re: [lwip-users] LWIP slow web server only with Windows OS request

[Marco Giammarini]

In attach you can find two trace captured with Wireshark. One with Windows, and 
one with OSX.

Thanks for your helps.

Regards,
Marco

home_page_loading_osx.pcapng
Description: Binary data

home_page_loading_win.pcapng
Description: Binary data

> Il giorno 17 set 2021, alle ore 12:15, goldsimon@gmx.de ha scritto:
> 
> 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, goldsimon@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