Subject: Re: TCP communication for raw image transmission

From: Rick Jones <[email-masked]>
Date: Thu, 05 Jan 2012 10:32:58 -0800

On 01/05/2012 01:55 AM, Eric Dumazet wrote:
> Le jeudi 05 janvier 2012 à 10:48 +0100, Jean-Michel Hautbois a écrit :
>
>> It does not seem to work :
>> netperf -H 192.168.0.1 -l 10 -t UDP_STREAM
>> MIGRATED UDP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
>> 192.168.0.1 (192.168.0.1) port 0 AF_INET
>> Socket  Message  Elapsed      Messages
>> Size    Size     Time         Okay Errors   Throughput
>> bytes   bytes    secs            #      #   10^6bits/sec
>>
>> 106496   65507   10.01        1836      0       0.00
>> 419227124           0.00      536870912              0.00
>>
>
> Thats because netperf -t UDP_STREAM sends big UDP frames by default,
> that must be fragmented, and defragmented on destination. Maybe some
> frags are lost.

There is also the question of the bogus values on the second line. 
There are some "fixed in top-of-trunk" issues in that area with respect 
to the migrated UDP_STREAM results printing.  The top of trunk also has 
a netperf control message size change, which means you have to make sure 
to update both sides to the top-of-trunk.  (Netperf has never 
"supported" mixing versions though doing so has often "worked.")

rick jones