[lwip-users] Re: tx badnwidth

[Chen]

Sorry, forgot to include the result:

payloadsize=100, about 6 seconds
Payloadsize=200, about 3 seconds
payloadsize=400, never finish
payloadsize=500, never finish
payloadsize=1000, 3 minutes
payloadsize=2048, over 3 minutes

>>>>>>>>>>>

Just a tight loop after the connection:

char dummy_data[2048];
total=10000000;
count=0;
do{
    l=lwip_send(clientfd, dummy_data,
payloadsize, 0);
    count =count+l;
}while (count<total)

Just try different payloadsize, for example, 100, 500, 1000, 1500, 2000, and you should see the result.


From:   Francois Bouchard
Subject:        Re: [lwip-users] Re: lwip-users Digest, Vol 67, Issue 6
Date:   Tue, 3 Mar 2009 14:59:43 -0500

Weird,
How long for a payload of... let's say 1400 bytes?
How do you measure/calculate the Bandwidth?

>>>>>>>>>>>>


The TCP's tx bandwidth is greatly affected by the size of payload for lwip_send.

My test is to send out

1000000
bytes of data as fast as possible (via TCP connection, such as
telnet)

If payload is 100 bytes, it takes only a few seconds to send out all the
data. If the payload is 2048, it takes a loooooooooooong time

Any comment?


> Subject: Re: [lwip-users] Re:
> lwip-users Digest, Vol 67, Issue 5
> To: Mailing list for lwIP users <address@hidden>
> Message-ID:
> <address@hidden>
> Content-Type: text/plain
>
> On Tue, 2009-03-03 at 09:05 -0500, Chen wrote:
>
> > 2) When I lwip_send too much data, the program actually crashes ---
> I
> > will investigate   more on the cause
>
> Thanks for investigating - it should work fine.  More details of
> what
> goes wrong, and what you do to cause it to go wrong would help.
>
> Kieran