In first two test case (No 1~27) test case

It takes 2.6s for the 1500 bytes date,  received in echo server. (check when
server get the PUSH 476 data)

In TCP_NODELAY test case (No. 28~56)

It only takes <1.2s for server received 1500 bytes. (check when server get
the PUSH 476 data)

Why TCP_NODELAY will cause the send performance changed much.


On Tue, Dec 29, 2009 at 9:23 PM, yueyue papa <[email protected]> wrote:

> I attached my test data.
>
> No.1 ~ 13.  xxx.8.130 --->  192.168.8.94(echo server)
>                  1500 bytes send/received about 3.5s (connect, send,
> receive, disconnect)
> No 14~ 27 the same.  3.5s
>
> No  28~ 40  set TCP_NODLAY
>                   3.0s about 500ms faster (connect, send, receive,
> disconnect)
> No 41 ~ 56   the same as previous
>                    3.0s
>
> In normal case:  there will be 1.5K data send, and received. I tried to
> make response the faster as possible.
>
> Is there a suggest solution?
>
> Whether the TCP DELAY is my performance killer?
>
> Thanks for help
>
> On Mon, Dec 28, 2009 at 4:57 PM, yueyue papa <[email protected]> wrote:
>
>> Hi all,
>>
>> I have a question on lwip ACK delay.
>>
>> Echo sever is used
>>
>>      lwIP    <-------------------------> PC WINDOWS
>>                --------------Send------>
>>                   <- - -windos ACK
>>                <------Echo back------
>>                   - -lwIP -tcp ACK -  - - >
>>
>> I send  2047 data, (mtu is 1024).
>>
>> driver send  1024  firsst
>>                   1024 send
>>
>> In wireshark, I could see the ACK delay.
>>
>> if small data, 123 byte,  lwip ACK send about 7xx ms
>> if  1024 data,  lwIP ACK is about 1s
>>
>> so 2048 data will be get after 2s.
>>
>> >>How could I change the default ACK delay?
>>
>> I tried to let lwIP ACK remote as quick as possible.
>>
>> Thanks
>>
>>
>>
>
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