[mythtv-users] Software changes required when switching CPU from single-core to multi-core?

[Craig Huff]

On May 25, 2011 7:44 AM, "Raymond Wagner" <raymond at wagnerrp.com> wrote:
>
> MythTV runs multiple processes, and each of those processes has multiple
> dozen threads, and among those threads there are multiple independent
> pathways not locked under shared mutexes.  What you may be thinking of
> is software video decoding, which is limited to single threaded
> operation by the decoding libraries, ffmpeg.  Even that is not entirely
> true, because multi-sliced h264 can be decoded in multiple threads, and
> the decoding profiles default to two threads in this case.  That is the
> _only_ option pertaining to threading that you can control in MythTV
>
> The Athlon 64 3200+ is a 2GHz socket 939 chip.  The Athlon 64 X2 3800+
> is a 2GHz dual core socket 939 chip.  You do not have an Athlon II, as
> that is a whole new architecture with a whole new incompatible socket.
> Your new chip is exactly as fast as your old chip in single threaded
> operations, and aside from some shared resources like memory and bus,
> should have roughly double the performance on multi-threaded operations.
>
> You are running an unstable version of MythTV on the 0.23-fixes branch,
> several hundred revisions prior to stable release.  This may very well
> be causing a number of your problems.  Other possibilities could be a
> nearly full hard drive for either recording, or database storage, or a
> damaged database that is causing excessively long queries when under
> heavy recording load.  It should be completely independent of your CPU
> swap, which is likely to have just coincidentally happened at the same
> time these problems started to appear.
>

Wow!  Thanks for the detailed reply.  As for the Athlon II vs. 64, you are
no doubt right.  Serves me right for trying to go from memory.

Now, your reply raises new questions:
1) How do I upgrade to a stable version, given that I'm using Mythbuntu;
preferably 0.23.xxx, unless I have been misreading the list talk about 0.24
issues -- all my recordings are from a pair of PVR-500s as I only have
Comcast DTAs as video sources.
2) What, in this case, constitutes a nearly full HD? > 90%? > 80%? ...? Or
is this one of those wonderful cases of "It depends" ;-)  FWIW, the
partitions boot, root, swap, and var are on an 80 GB IDE drive and videos
are spread across (one each) 250GB, 500 GB, & 1 TB drives.
3) DB damaged in some way that the optimize_DB perl script doesn't handle?
(I run the script as part of the standard shutdown process that occurs when
there will be a long time before the next recording event.)

TIA for any additional advice.
Craig.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.mythtv.org/pipermail/mythtv-users/attachments/20110525/17e0d4f0/attachment.html