[mythtv-users] Backend settings for max simultaneous jobs and cpu usage

[Jim Stichnoth]

On Wed, Dec 28, 2011 at 9:28 AM, steve <networks1 at cox.net> wrote:
> Greetings and happy holidays.  I am looking for advice on how to choose
> settings for Max simultaneous jobs and CPU usage on the backend setup.
> I have a Core 2 Duo E8400 3ghz processor, and want to make best use of
> it.  But I have looked around the wiki and done some searches on this,
> and am not turning up much.  What are the principles for selecting
> settings for two these options?

In addition to Mike Dean's general advice, here's my own personal
experience.  My backend has a Core 2 Duo E5200 @ 2.5GHz.  I have it
configured to allow 3 simultaneous jobs, at the "Medium" CPU setting.
The reasoning is that (at least for MPEG-2 recordings) commflagging
proceeds significantly faster than realtime, so when commflagging
starts concurrently with the recording, it ends up not using all of
the CPU.  I have never seen any problems with this setting and I have
probably had it this way for 2 years.  The other observation is that
often enough, I have 3 recordings at the same time, so allowing 3
simultaneous jobs allows some amount of fairness to the commflagging.
(This would be a lot less of an issue with the smart job queue that
Mike mentioned.)

One thing, though.  If you are in the habit of doing lossless
transcoding, you may want to be careful about allowing more than one
of these at a time, as they are extremely I/O bound and can interfere
with a recording happening at the same time.  The backend setup
doesn't let you restrict jobs according to job type.

Jim