[mythtv-users] Mythfrontend idle cpu consumption help

Jim Stichnoth stichnot at gmail.com
Tue Nov 3 21:34:10 UTC 2009

On Tue, Nov 3, 2009 at 7:09 AM, Daniel Kristjansson
<danielk at cuymedia.net> wrote:
> On Mon, 2009-11-02 at 14:07 -0800, Brad Templeton wrote:
>> On Fri, Oct 30, 2009 at 12:22:22PM -0400, jansenj wrote:
>> I have found much greater use of CPU by the more recent mythfrontends
>> over the last year in general.   For example, while my system would
>> get decent idle times playing HD content and run quietly, now the
>> computer is routinely heating up (and running the fan loud) with
>> nothing else on the machine sucking CPU except xorg and mythfrontend.
>> (ie. no mythcommflag, which was the only reason the fan would get
>> loud before, or perhaps a runaway firefox page.)
> I can't speak for your particular machine. However I had
> noticed this too on one frontend but after some investigation
> found out that the 0.21 MythTV never allowed the CPU to enter
> a low power state, so it only appeared to be using less CPU.
> When I forced the CPU out of powersaving mode the CPU usage
> looked the similar when using the same theme.
> Some themes do consume more resources because they use alpha
> blends, animations and clocks. This is especially true if you
> use the Qt renderer, which does these things using the CPU
> instead of the GPU.
> During my investigation I also noticed the plasma rendering
> engine in KDE 4.x consumes more resources than any other
> application on the machine. For a dedicated MythTV machine
> it is a good idea to use something lightweight instead.

I have been noticing the same kind of behavior since moving to 0.22,
which I am running on 3 IONITX frontends (one of which is also a slave
backend).  After booting up, the frontend consumes about 2% CPU
displaying the main menu, which is fine.  Over the next few days, this
CPU usage gradually increases, until it's at around 10%.  When it gets
to 10%, the response time gets much worse.  For example, from the main
menu, selecting Watch Recordings may pause for 4-5 seconds while still
displaying the main menu, then it displays a blank Recordings page for
another 5+ seconds, and finally displays the recordings.  The same
sluggish performance happens for MythVideo as well.

When it reaches this funk, restarting the frontend doesn't help.  It
comes back up consuming 10% CPU like before.  I haven't found anything
other than rebooting to get the zippy performance back.  (Makes me
feel like it's a Windows machine!)

Any ideas for explaining this behavior?


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