[mythtv-users] Feature request: realtime commercial flagging

[papenfuss at juneau.me.vt.edu]

> The CPU isn't the only constrained resource.  Commercial flagging does a
> _lot_ of disk reads, which can keep more important reads (or even writes)
> from completing when needed.  I've definitely noticed some playback
> hiccups when commercials are getting flagged, even with mythcommflag in
> its nice-and-also-sleeping mode.

	Fair enough.  I must say that I've used linux for my primary OS for 
over 6 years now, and the IDE performance has always seemed to leave a lot to 
be desired.  I don't think it's inherently linux, but rather IDE sucks.  
Winders is even worse... and I can't afford SCSI anymore.

> 
> A related question: do the frontend and backend do readahead on playback,
> and how much?  That is, how long can the disk block on playback without
> causing stutters?  It seems like a little more readahead (like skip
> protection on a portable CD player) would eliminate a lot of stutters.
> 
> --Patrick
> 

	It seems like that would help, although it might be a deeper problem.  
If it's an I/O latency problem, the lower-priority task (commercial detection) 
might be preventing the higher-priority task from getting the I/O it needs 
before the *card's* buffer overflows.  Adding a big fat memory buffer might 
help, but it should be relatively easily configurable too.  I don't see the 
reason why 1/4 Gig of memory should be necessary in the current mythtv, anyway.

	How does the low-latency kernel patch fit into this?  

-Cory


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