[mythtv-users] rPi3 ram consumption causing playback freezing

[Stefan Davids]

On 15/07/17 18:15, Tim Draper wrote:
> i've had my rpi3 for a few weeks now and on the whole, it's been next to perfect.
>
> recently, i've found that playback can sometimes be extremely laggy so i initially went with a nightly reboot to freshen everything up. this sorted things getting out of hand over a few days.
> however i think i've now found that if i play something in the morning/over lunch, then come dinner time the playback will be laggy.
>
> 'htop' is showing ~85% general usage, ~1% buffer, and the remaining ~14% as buffer cache.... which brings total ram consumption to completely maxed out @ 100%.
>
> clearing the pagecache sorted the problem out with the following command without a reboot being required:
> sync; echo 1 > /proc/sys/vm/drop_caches
>
>
> the rpi config i use is as follows:
> rasbian latest & fully updated, mythtv-light used as per wiki.
> gpu_mem=192 (so 796MB remaining for the system)
> vm.swappiness=10
> MythFE theme: MythCenter-wide
> rpi3 gets left on 24/7 and playback is stopped when not using it  (going back to either recorded tv/main menu)
>
> what'd be the best way to sort this problem out? is there something i can tweak to properly stop it happening in the first place, or will running cron with the drop_caches cmd be the way forward?

I've got an rPi3 I leave on 24/7, gets used 2 or 3 times a day at least 
and doesn't experience any memory issues and seems pretty flawless as 
long as you playback what's expected to work.  256MB for gpu though.

Does nothing much apart from running mythtv and squeezelite and 
currently free says:
$ free  -h
              total       used       free     shared    buffers    cached
Mem:          733M       687M        45M        38M        49M      228M
-/+ buffers/cache:       409M       323M
Swap:          99M       8.3M        91M

I haven't much fiddled with the default mythtv setup apart from using 
Steppes theme and the mythtv-light package.  I last updated about 2 
weeks ago (when the interlacing issues were fixed).  I can see a kernel 
update waiting though...  I'm currently on:

Linux pi-3 4.9.28-v7+ #998 SMP Mon May 15 16:55:39 BST 2017 armv7l GNU/Linux

Maybe there's a bug in the new kernel update if yours is a newer 
version?  Either way I won't be updating soon!  I guess doing the drop 
cache regularly with cron would work around it until it gets fixed; or 
try downgrading the kernel.  Or maybe turn off swapping completely and 
see if that makes a difference.

Sorry not much help.

Stefan