[mythtv] Ticket #10414: HDHomeRun: Bad Recordings

Bruce Taber b.taber at comcast.net
Sun Mar 11 18:40:19 UTC 2012

On 03/11/2012 12:25 PM, David Engel wrote:
> On Sun, Mar 11, 2012 at 12:13:21PM -0400, Daniel Kristjansson wrote:
>> On Sun, 2012-03-11 at 10:50 -0400, Tom Lichti wrote:
>>> On Sat, Mar 10, 2012 at 8:41 PM, Gary Buhrmaster
>>> <gary.buhrmaster at gmail.com>  wrote:
>>> Then may I respectfully suggest that we are going down the wrong path
>>> on this? I've used the default network settings, the tweaked settings
>>> on the page Daniel suggested, and Daniel's own settings, and none of
>>> them has made a difference. The only thing that made any noticeable
>>> difference was Daniel's commit the other day, but that only made
>>> recordings go from completely un-watchable to highly annoying (and
>>> still un-watchable).
>> Thanks for testing the network settings though it was important
>> to eliminate that possibility. I've also gotten a report off-line
>> that logging is not the culprit. So far the only commonality
>> appears to be high CPU usage. My commit slightly lowered CPU usage,
>> but increasing that timeout further won't do much.
>> I plan to run an oprofile on mythbackend with a couple HDHomeRun
>> recordings going sometime in the coming week. Even though I'm not
>> seeing the issue on my i5, it should still show where CPU is being
>> used and hopefully show something useful.
> I'm running a git bisect today to try to find when the higher CPU
> usage started.  That might not be the real cause of the problem, but I
> still want to figure that out.
> David
I began to see these types of bad recordings about the same time as the 
commit for the code that flags them as bad. Back in November? I don't 
believe that was the culprit but more of a coincidence. I don't really 
have a way to determine that beyond a shadow of a doubt.

I've gone round and round in testing everything I could think of to see 
if I could identify the problem. The last step has been to replace the 
slave backend system with one that is more powerful. That has seemed to 
alleviate the problem. The same drives from the old system were moved 
into the new. I think most of the bad recordings that still exist in my 
setup are ones that were recorded on the previous slave. I hadn't 
noticed any incidences of high CPU usage but they may have been missed. 
And I haven't seen any new recordings with the same problem.


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