[vdr] Instability with recordings on VDR-1.7.4 when recording to a NTFS partition

Klaus Schmidinger Klaus.Schmidinger at cadsoft.de
Mon Mar 23 08:35:58 CET 2009


On 23.03.2009 01:09, Niedermeier Günter wrote:
>> There must be an other problem that's causing this, but since this doesn't
>> happen here on my system, I'm afraid you'll need to do the debugging ;-)
> 
> Which changes have been made between 1.7.2 and 1.7.3 in
> file writing mechanism?
> 
> Not codechanges, because I dont understand them, but in words please.
> E.g. blocksize changed from xxx to yyy changed algo. changed cache or
> something else which can influence the performance.
> 
> I found out, that in 172 the most time up to 20 stream data blocks are
> transmitted via NFS between one "NFS WRITE CALL / WRITE REPLAY" and
> "NFS COMMIT CALL / COMMIT REPLAY" combination and the next one.
> 
> In 173/174 the number of stream data blocks decreases to an amount of
> 5 blocks maximal. Therefor the number of "NFS WRITE CALL / WRITE REPLAY"
> and "NFS COMMIT CALL / COMMIT REPLAY" combinations increases up to
> 4 to 5 times higher than in 172.
> 
> This produces an enormous overhead, and this overhead could be
> reasonable for the two MegaByte/s networkoverload above the normal
> load with 1 MB/s per stream.
> 
> Perhaps Klaus, you have an idea.

I believe I do. With PES recordings, data was written to the file
in larger chunks, while with TS recordings it is written in blocks
of 188 byte (TS_SIZE). I'll chnage cFrameDetector::Analyze() to
handle more data at once.
Will try to provide a patch for testing tonight.

Klaus



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