[mythtv] Backporting some of MiniMyth2 patches to mythtv master?

[David Hampton]

On Fri, 2017-10-13 at 16:44 +0200, Piotr Oniszczuk wrote:
> Guys,
> 
> I see ongoing process of opening of myth to new code contributions
> (which is finally great!)
> 
> Will You consider to back port some of MiniMyth2 patches to myth tv
> master code?
> 
> I’m using mm2 patch set in my production system without any issues
> since years while enjoying greater functionality&flexibility.
> Also whole mm2 community runs them with great success I believe.
> 
> If You think it is worth to do - we can discuss patch-by-patch here
> and dev team can decide - is it worth to merge or not.
> 
> So lets try with first candidate:
> 
> https://github.com/warpme/minimyth2/blob/master/script/myth-master/my
> thtv/files/0324-disable-caches-pruning.patch
> 
> Patch allows to disable cache pruning by setting UIDiskCacheDays to
> -1.

Sure, I'll add support to disabling pruning by setting the value to -1.
 I'm also willing to change the seven day default to whatever the group
thinks is reasonable.  One or two months also seem like reasonable
values.

> Why useful: 
> If frontend is used as appliance with sleep/resume regime with mode
> where mythfrontend process is exited at sleep and started at
> appliance resume - cache pruning can considerable increase
> mythfrontend start time (on my ION2 it is 11->19..21sec).

I don't see times anywhere near that on my test machine, but you're not
the first person to report new startup/shutdown delays.  Thanks for the
feedback.

> Sure - this we can overcome by moving cache pruning to separate
> thread (which is also good idea IMHO)

I agree this is a good idea.  I'll have to investigate whether it will
require some sort of locking between deletion and cache lookups, or if
we can get away without the locking.  I think I'll probably also need
to disable the cache pruning on exit.

David

> But I have another argument to turn-off pruning some cases:
> 
> lets see 2 cases: 
> 
> a\ no pruning: 
> (-)bigger disk usage
> (+)no issue with lagging some images on UI (no cache)
> (+)quick, predictable start of frontend      
> 
> b\pruning
> (+)space on hdd saved
> (-)noticeable UE impact when playing with UI
> (-)mythfrontend startup sometimes so longer(*) than user thinks it
> hanged
> 
> For me in mm2 b\ wins clearly.
> 
> Patch allows to user to decide a\ or b\ 
> 
> (*) I have appliances where mythfrontend wasn’t restarted by weeks.
> Any restart triggers long (10-20sec) of cache pruning.
> 
> br
>  
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