[mythtv-users] small mythtv freezes ?

[Bruce Markey]

Tako Schotanus wrote:
> 
> 
> Bruce Markey wrote:
> 
>> Jelle Kalf wrote:
>>
>>> Hi,
>>
>>
>>
>> Hello,
>>
>>> Once every few seconds (especially when I run mythfrontend in the 
>>> background) I
>>> get small freezes every few seconds:
>>>
>>> 2003-11-24 18:13:00 prebuffering pause
>>> 2003-11-24 18:13:05 prebuffering pause
>>> 2003-11-24 18:13:22 prebuffering pause
>>> 2003-11-24 18:13:23 prebuffering pause
>>> 2003-11-24 18:13:27 prebuffering pause
>>> 2003-11-24 18:13:29 prebuffering pause
>>>
>>> dmesg output:
>>> saa7115[0]: decoder disable output
>>> saa7115[0]: decoder enable output
>>> saa7115[0]: decoder set picture bright=127 contrast=63 saturation=63 
>>> hue=0
>>> saa7115[0]: decoder set picture bright=127 contrast=63 saturation=63 
>>> hue=0
>>> saa7115[0]: decoder set picture bright=127 contrast=63 saturation=63 
>>> hue=0
>>> saa7115[0]: decoder set picture bright=127 contrast=63 saturation=63 
>>> hue=0
>>>
>>> I'm running on a Athlon XP2100+ with 1gb memory and hd's running in 
>>> UDMA66.
>>>
>>>
>>> Note: when I run Mythfrontend in the front and not zapping etc, I 
>>> don't have the
>>> problem. I do have the problem when zapping channels.. it flikkers 
>>> once or
>>> twice.
>>
>>
>>
>> There was a bug in 0.11 and earlier that would cause these
>> after a channel change until you paused or rewound for ~30scec.
>> If you are using 0.12 or later this doesn't happen but there
>> often can be one or two pauses after a channel change (I'll
>> tell you exactly why this happens then there will be a series
>> of replies saying I'm full of 'it because it doesn't match
>> what they imagine or assume ;-). 
> 
> 
> No,

Well, yes ;-). I was responding to the symptoms in the
message above, not what you've introduced below.

> it has nothing to do with one or two stutters after a channel 
> change, that's normal. This is about continuous stuttering that occurs 
> every second or so and is very slight but enough to be annoying. The 
> console is filled with messages about prebuffering pauses.

The prebuffering pause is unambiguous that the player had
to stop and wait for more frames. However, this isn't very
helpful in pinning down why new frames weren't ready in time.
 
> For me this only happens after a certain time, never in the beginning of 
> a recording.

Is it always in the exact same spot each time you replay
the same recording? Does it happen if you use jump ahead
to go that far into the recording or only if you let it
play for a certain period of time? Does the stuttering go
away if you pause or skip back once? Have you checked top,
free, sar, iostat, or whatever to see if paging activity
goes up when this is happening?

On this last question, there was a memory leak for a few
days last week. If you are using CVS from about a week ago,
it may be that it runs fine until the leak causes memory
to be paged out.

> CPU usage is low enough (mostly around 30%) so that should not have 
> anything to do with it.

CPU is a good first place to look but there can be other
throughput or latency issues that would foul things up.
For about two weeks during the solar storms I was having
mysterious periods of slowness over my 802.11g network
that would cause stuttering. I don't want to sound too nutty
but me thinks it was Sun spots. However, that's not my
diagnosis of your problem ;-).

--  bjm