[mythtv-users] Storage Groups: Usage Preferences

Chris Pinkham cpinkham at bc2va.org
Tue Mar 6 15:34:02 UTC 2007


* On Tue Mar 06, 2007 at 03:16:00PM +0100, Janne Grunau wrote:
> On Tuesday 06 March 2007 10:29:11 Chris Pinkham wrote:
> > It's a bit more complicated than that.  Myth uses weights to
> > determine what filesystem/directory to record to.  The following
> > default values are used:
> >
> >    SGweightPerRecording  = 10
> >    SGweightPerPlayback   =  5
> >    SGweightPerCommFlag   =  5
> >    SGweightPerTranscode  =  5
> 
> We might should think of using higher weight for lossless mpeg2 
> transcodes. They are the most IO demanding job we have.
> I'll look into it.

Actually now that I think about it, transcode in general may need
to be higher than recording because it involves both reading and
writing.  So SGweightPerTranscode could be at least 15.

I don't know if it does it, but the lossless transcoder needs
to honor the JobQueue CPU setting.  If that is done, then we
could make these weights dependent on the JobQueue CPU setting.
A transcode running at the Low CPU setting shouldn't use anywhere
near as many resources as one running at High.  The same holds
true for mythcommflag.

We could change SGweightPerTranscode to 15 by default and then
multiply SGweightPerCommFlag and SGweightPerTranscode by 0.5 (or
0.75) if the JobQueue CPU setting is Low or multiply by 1.5 if
the JobQueue CPU setting is High, that way we weight things more
if we know they'll use more CPU (hence higher disk I/O).

--
Chris


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