[mythtv-users] *Performance* of LiveTV auto recording?

[Steve Daniels]

> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org [mailto:mythtv-users-
> bounces at mythtv.org] On Behalf Of Pekka Savola
> Sent: 18 April 2006 19:58
> To: Discussion about mythtv
> Subject: Re: [mythtv-users] *Performance* of LiveTV auto recording?
> 
> On Tue, 18 Apr 2006, Steve Daniels wrote:
> >> I don't care about disk space.  My reason is performance.  I don't have
> >> too
> >> fast a system (P3/800), and watching LiveTV already gulps about 180 MB
> of
> >> memory and about 30-50% of CPU.  I have done no measurements, but I
> >> suspect a
> >> non-trivial part of that is due to disk-I/O (yes, DMA is enabled).
> >
> > A *doubt* that the high percentages come from writing and reading to and
> > from the disk respectively. Although you are using a lot of resources to
> > watch LiveTV, do you need these resources for anything else? What
> graphics
> > are you using? Try XVMC?
> 
> XvMC is not an option as the hardware (old Riva TNT2 card) doesn't
> support that.
> 
> This is an example with MythTV:
> 
> 25602 psavola   15   0  276m 101m  33m S 49.6 26.8   2:20.26 mythfrontend
> 25674 root      15   0  270m  29m 9784 S 17.4  7.8   0:15.42 mythbackend
> 
> Or two alternatives:
> 25390 psavola   15   0  223m  46m  27m S 43.6 12.4   2:01.05 kaffeine
> 
> 25521 root      15   0  266m  37m  16m S 35.8 10.0   0:18.92 xine
> 
> (Without deinterlace, CPU is 10-15% lower, but that'd probably apply
> to all of these.)
> 
> While I don't usually need most resources at the same time (though
> it's not atypical to have a dozen or two Firefox windows open, which
> take quite a bit of memory :-), this is causing some jumpiness in
> MythTV.  I haven't traced the roots of that jumpiness yet, though my
> suspicion is lack of memory (I only have 384MB) when multiple other
> windows are open, leading to swapping, which isn't good especially
> when LiveTV is already engaged in heavy disk I/O.
> 


Well I think the long and the short of it is, if MythTV was running on it's
own on this box it could be fine? But with other stuff stealing memory and
causing swapping it's just going to be plain ugly. Seeing that play back is
only about 6% higher than caffeine is very nice to see, especially with all
the MythTV goodness.

(There's no real point arguing a case for MythTV to have an option of having
it run without writing the stream to disk first, unless however your or
someone you know is going to write it and maintain it for all the future
versions..)

Sorry that I can't be any more help, other than, RAM is cheap ;-) Also, just
because you can run mythfrontend, mythbackend, and a dozen other desktop
apps at the same time on the same PC doen't mean you should ;-)

Steve Daniels