[vls-devel] Re: Occasional crazy problem with vls

[Jean-Paul Saman]

Andrew de Quincey wrote:

>>Which kernel are you running?
>>    
>>
>
>2.4.21
>  
>
Does it have the anticipatory patch?  I am not sure ??

>I think basically the problem is we didn't choose those servers to have 
>particularly great disk IO throughput.. this streaming of one file is 
>basically just a feature to keep a particular client happy. We use them to 
>read the data to be streamed directly from DVB or MPEX cards and then send it 
>to the network interface. 
>  
>
Could it be that the disk is fragmented? Because if the files were to 
lay in one contigous chunk, then  you wouldn't see this problem. I guess 
you also use the same disc for the root filesystem without any additonal 
partitions accept for the swap, right?

>In the future, we would properly spec streaming machines etc.. but in the 
>meantime. sigh.
>
>Mind you, I would have thought it would be able to cope with streaming one 
>5mbit/s file. 
>  
>
I would expect the same.

>Anyway, the problem only occurs infrequently. We're not in the habit of 
>uploading huge files; basically once the system is going, it gets left alone. 
>My patch seems to fix the runaway problem if it occurs, so I'm quite happy 
>with it as it is now. I'll tidy up the patch and commit it tomorrow.
>  
>
Ok.

>Could this problem affect our DVB streaming as well, but we've never noticed 
>it? Because the speed at which DVB data can be retransmitted by VLS is 
>limited by the speed at which it is received by the DVB hardware, it doesn't 
>matter that VLS's timing goes off.
>
>  
>
If the stream is not saved to the disc, then the problem will not occur. 
VLS has to compensate a bit for the drift or run completely in slave 
mode for the DVB card. The DVB satellite determines the clock in this case.

-- 

Many greetings,
Jean-Paul Saman

Consultant/Freelancer
--------------------------------------------------------------
VLC iPAQ maintainer                    http://www.videolan.org
RedHat Certified Engineer         RHCE number: 807202745005548
--------------------------------------------------------------



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