[mythtv-users] Mythbackend hogging CPU, causing IO problems

[Ryan Steffes]

On 6/4/06, Michael T. Dean <mtdean at thirdcontact.com> wrote:
>
> On 06/04/2006 12:15 AM, Ryan Steffes wrote:
>
> > On 6/3/06, *Ryan Steffes* <rbsteffes at gmail.com
> > <mailto:rbsteffes at gmail.com>> wrote:
> >
> >     I just upgraded to recent SVN this week (and tried again with this
> >     mornings) and mythbackend is running oddly.  It starts out fine,
> >     then, after 5 to 20 minutes, it starts hogging the CPU to the
> >     point where it causes ivtv to flake and throw those write errors,
> >     and my log starts filling up with
> >
> >
> >
> > Incidentally, this is directly related to mythtranscode running.  I
> > turned off mythtranscode, and now everything is running correctly.
> > However, I don't believe it's a straight IO problem, because I can
> > actually load the box more than it was before (watching a movie, while
> > transcoding a DVD with mencoder, while recording, with mythcomflag
> > running on this machine and a slave, and the slave running
> > mythtranscode on it) without the problem recurring.  It's the
> > mythbackend process that shoots to 90ish percent CPU though and throws
> > all the errors, not the mythtranscode process.
>
>
> What do you have set for Job Queue CPU usage (in mythtv-setup, General,
> "Job Queue (Host-Specific)")?
>
> CPU Usage
>     Low
>     Medium
>     High
> This setting controls approximately how much CPU jobs in the queue may
> consume. On 'High', all available CPU time may be used which could cause
> problems on slower systems.



Job Queue is set to Low, I should have mentioned that.  The CPU is an AMD
2400+ (running at 1660MHz) and it's got a gig of RAM.  It's not the CPU
being taxed that's causing the problem, it runs fine all night when it's
happily folding away (I run folding during the evening mostly for heat
issues), and it's always been fine letting transcode and mencoder peg out
the CPU before this.  It appears to be some interaction between mythbackend
and mythtranscode that is causing something to thrash.

Ryan
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