[mythtv] DVB recording issues

[Matt Lovett]

On Thu, 24 Mar 2005 00:40:13 +1000, Jason W <jason at backtick.org> wrote:
> 
> Right now I am doing a test by recording 3 different channels at once.
> Initially, watching the recordings as they are in progress on a remote
> frontend, it seems fine without any visible errors. Within a few minutes
> I am having buffering problems. Load average is up to 18 and peaked at
> 23 before I canceled the recordings. my myth log shows a lot of
> 
> 2005-03-24 00:28:02.644 IOBOUND - blocking in ThreadedFileWriter::Write()
> 
> as well as the continuity errors from above occurring on all cards.

On my system, the logging of bad packets (both the "corrupted packed
detected, dropped" and the subsequent "continuity error" messages)
seem to add up to significant cost. My combined front/backend on epia
doesn't have many spare cycles, but even when I used to run on a full
PC I ran into issues.
What's worse, once we start getting the messages the system tends to
degrade, with the disk thrashing back and forth between the video its
trying to record and the log. (Log writes cause a sync, the system is
busy, we get more messages....)

I think the logging messages should probably dropped, and instead keep
counts through the recording.... or try to measure the rate of errors
and stop recording if the rate is too high to give useful results...

But that's tricky code that I haven't written ;)

Cheers,

Matt