[mythtv] scheduler: "The Nanny" - tipping point into madness

Robert Kulagowski bob at smalltime.com
Mon Apr 12 20:45:47 EDT 2004

Being in a diverse household with a wide range of ages, one of the 
programs that I was asked to schedule is "The Nanny", (TN) which in my 
lineup plays multiple times throughout the day.  In the 9 days of data I 
have, it appears that there are ~ 50 episodes.

If I _don't_ have TN set to record (all episodes, all channels, keep 
all), mythbackend will sit at around 200MB according to top, with about 
230 programs to be scheduled when I run mythbackend --printsched |wc -l

If I do have TN scheduled, I get stuff like:
"Out of memory (Needed 1484259344 bytes)" showing up on my console.

The scheduler can take 3-4 _minutes_ to run, instead of 2-4 seconds, and 
myth can just keep on eating memory until init kills it.  Everything 
becomes laggy (load average climbs past 8 or 9), because kswapd is 
trying it's hardest, but 512MB phys + 512MB swap sometimes still isn't 

Hardware specs:
master, p4 2.8Ghz, 2xPVR-250, 512MB
slave, p4 celeron 2.0 Ghz, 2xPVR-250, 512MB

I haven't seen the presence of the slave and its two tuners impact the 
scheduling too much.  It still takes a long time.

What sort of troubleshooting can I help with?

This is with current CVS with today's scheduler commits.

Here's some more data.  Before scheduling TN, we have 230 programs, 
taking up 200MB of virtual.  With TN, we have 292 programs, taking up 
328MB of virtual.  With TN + JAG, we have 310 programs taking up 524MB 
of virtual.

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