[Udpcast] Experiencing reproducible corruption when using udpcast-20090912

John Eisenman jice at mylife.com
Thu Sep 17 10:09:25 CEST 2009


John Eisenman wrote:
> John Eisenman wrote:
>   
>> I'm new to udpcast and so may be doing something wrong.  However, I find
>> that with the latest two versions (udpcast-20090912 or
>> udpcast-20090830), I experience repeated file corruption.  I've had
>> better, but not perfect,  success with an old version (udpcast-20071228).
>>
>> In order to test, I made an ordered file, 500MB in size:
>>
>> cl6 tmp # ls -l test-52428800.dat
>> -rw-r--r-- 1 jice jice 524288000 Sep 15 17:52 test-52428800.dat
>> cl6 tmp # head -14 test-52428800.dat
>> 000000000
>> 000000001
>> 000000002
>> 000000003
>> 000000004
>> 000000005
>> 000000006
>> 000000007
>> 000000008
>> 000000009
>> 000000010
>> 000000011
>> 000000012
>> 000000013
>>
>> I find that every time I send and receive a file, it is the correct
>> length.  However, certain data is missing and other data is repeated.  
>>
>> Here is an example of my command line to send the data:
>>
>> udp-sender --log udpcast.log --bw-period 1 --nokbd --min-receivers 1
>> --min-wait 5 --portbase 9010 -f test-52428800.dat --pointopoint
>>
>> Here is my command line to receive data:
>>
>> udp-receiver  -f test2 --nokbd --portbase 9010
>>
>> I have test result files that I can provide if they would be helpful.
>>
>> I am running under Gentoo on AMD64 processors.  I've tried under two
>> different kernels:
>>
>> # uname -a
>> Linux cl7 2.6.20-gentoo-r8 #1 SMP PREEMPT Wed Aug 22 14:28:25 PDT 2007
>> x86_64 AMD Opteron(tm) Processor 246 AuthenticAMD GNU/Linux
>>
>> # uname -a
>> Linux m231 2.6.30-gentoo-r4pb #2 SMP Thu Aug 27 18:41:51 PDT 2009 x86_64
>> Quad-Core AMD Opteron(tm) Processor 2374 HE AuthenticAMD GNU/Linux
>>
>>
>>
>>   
>>     
> Additional information:
>
> By running in async mode (and setting an fec), I find that I am able to 
> produce a non-corrupt output file.  Perhaps this provides a clue as to 
> the source of the problem.
>
>
>   
Another odd clue.  The corruption appears to depend on running the 
udp-sender (udpcast-20090912) as root.  When running the udp-sender as 
another user, there is no corruption. 

Yes, quite odd.  But, does it ring any bells?





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