[mythtv-users] General ways to fix lag on liveTV

[George Mari]

Jonathan Seawright wrote:

[deleted]
> 
> Have you run top while playing back live TV?  Is your CPU maxing out
> under live TV?  My guess is no, but it's good just to be sure.
> 
> The CPU isn't maxing out..and when I run top usually mythfrontend shows up 
> at top.
> 
OK - good.

> IMO, it's more likely you have I/O contention.  Do you have only the
> recording files on the LVM?  If if also contains the MySQL files, and
> the directory that myth logs to, that's two more things that are taking
> up your available I/O.
> 
> Yeah, great point, thing is, would that be hard to reconfigure?
> 
I'm not too familiar with LVM tools, but it certainly is doable.  A bit 
of research on your part on the relevant man pages would be needed.  If 
you don't have any other physical drives in the system, easiest thing 
may be to add another SATA drive, LVM that together with your existing 
SATA drive, and keep all your system files and MySQL tables on your 
original ATA 120GB drive.

> Do you have the same skipping when watching previously recorded content
> and recording another show simultaneously?  That would be another good
> data point to work from.
> 
> I dont get skipping when I watch anything pre recorded. I've watched a 
> recording as it was being recorded, and it was crystal clear.
> 
Here is a recent thread for the mailing list archives that talks about 
the same subject.  You might find some useful info in it:

http://www.gossamer-threads.com/lists/mythtv/users/278653#278653

Generally, watching LiveTv is the most intensive thing you can do with 
MythTV, and any shortcomings in your particular setup will become evident.

> Try temporarily turning off logging on both the front end and back end
> to see if this improves things.
> This made a difference for me when I had fewer drives in my system,
> until I separated things a bit more.
> 
> How can I turn off the logging? (I'm not clear where the options are)
> 
You may not even be doing any logging - I don't know if you've turned it 
on previously or not.  It also depends on how you're running the 
mythfrontend and mythbackend executables.  If you're just typing in 
"mythfrontend" everytime, you aren't saving things to a disk log.  On 
the backend, it again depends on your distro.  I run FC6, and I had to 
edit my /etc/init.d/mythbackend file to set the runtime options I wanted.

You'll want to search the wiki and mailing list archives for more 
in-depth info.  Here are some starters:

http://www.mythtv.org/wiki/index.php/Optimizing_Performance
http://www.mythtv.org/wiki/index.php/File_storage