[mythtv-users] Optimizing rec./livetv tuner orders

Michael T. Dean mtdean at thirdcontact.com
Sat Jul 21 15:08:24 UTC 2012

On 07/21/2012 11:03 AM, Michael T. Dean wrote:
> On 07/20/2012 07:35 AM, warpme wrote:
>> Hi *
>> I have quick question regarding rec/livetv tuner orders optimization.
>> Let assume we have 2 phy tuners (a,b) with 4 vritual each (1...4).
>> I want to achieve: minimal rec-livetv collisions, best livetv 
>> availability, in case of resource races rec. should have priority 
>> over livetv.
>> What setup will give meet above conditions with lowest scheduler load:
>> <tuner>:<rec.order>,<livetv.order>
>> case1:
>> tun_a1: 1,8
>> tun_a2: 2,6
>> tun_a3: 3,4
>> tun_a4: 4,2
>> tun_b1: 5,7
>> tun_b2: 6,5
>> tun_b3: 7,3
>> tun_b4: 8,1
>> or
>> case2:
>> tun_a1: 1,2
>> tun_a2: 1,2
>> tun_a3: 1,2
>> tun_a4: 1,2
>> tun_b1: 2,1
>> tun_b2: 2,1
>> tun_b3: 2,1
>> tun_b4: 2,1
>> Assuming, that for the same order value algorithm use tun_nr value 
>> for selection, it seems that for rec. order, case1 will result with 
>> the same scheduling order like case2. For livetv not.
>> But functionally, I think, both cases will offer exactly the same 
>> user experience.
>> Has case2 any sched. performance gains over case1 ?
> Never, ever, do case 1.  It will completely break multirec (meaning 
> you'll record things from the same multiplex using different physical 
> tuners).  This is why the UI only allows you to set the schedule order 
> or Live TV order on the capture card--not the individual virtual tuners.
> Case 2 is what you want--or something along that line, but with more 
> physical tuners (as with only 2, the likelihood of recordings 
> preventing you from being able to "own" a tuner for Live TV is very high).

Actually, now that I look at it, again, case 1 is identical to case 2 
for recordings--I had misread it, thinking it was the broken 
configuration where people were alternating virtual tuner order.

That said, you want case 2, still.  It will result in a 
far-more-efficient allocation of tuners for Live TV, resulting in fewer 
interruptions to Live TV usage (which is good, since the popup that says 
that the tuner is required for Live TV is broken and generally causes 
problems to both Live TV and recordings).  And, use the UI to set it up, 
don't hack the DB.


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