[mythtv-users] BE (0.25) memory leak?

Gavin Whitehead gavin at alabastercranium.demon.co.uk
Fri Jul 6 21:02:45 UTC 2012

On 04/07/2012 19:50, Gavin Whitehead wrote:
> On 03/07/2012 23:05, Gavin Hurlbut wrote:
>> On Tue, Jul 3, 2012 at 2:50 PM, Gavin Whitehead
>> <gavin at alabastercranium.demon.co.uk>  wrote:
>>>      VIRT    880m
>>>      RES     81m
>>>      VIRT    942m
>>>      RES     74m
>>>      VIRT    951m
>>>      RES     83m
>>> So that consumed ~340MB in 15 minutes.
>> How so?  your VIRT and RES numbers are saying there is no significant
>> growth in mythbackend at all.
>> Using "free memory" from free is not a good way to judge memory leaks
>> in a program.  This memory includes the buffer caches and other stuff
>> used by the kernel, which is almost assuredly where the memory usage
>> is.  As for actual memory used by mythbackend, you have shown nothing
>> that indicates that at all.  The Linux memory management system is
>> complex and confusing for most users.
>>> If I now stop and restart the BE I don't the memory back.  After the BE
>>> process has been stopped the free memory reported by top stays about 
>>> the
>>> same.
>> Of course it is.  The kernel is keeping the memory for its buffers 
>> and caching.
>> I don't see a problem here.
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>> mythtv-users at mythtv.org
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> I starter 'worrying' about the memory because after recording stuff 
> the GUI applications (FE, Firefox, XBMC) seemed sluggish.  And after a 
> reboot they seemed 'nippy'.  Also, the only time I've ever noticed my 
> system use swap space is after 'free memory' had dropped to almost 
> zero (during/after recording).
> I'll play some more and try and convince myself that I am imaging the 
> sluggishness.
> Thanks for the response.
> Gav
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> mythtv-users at mythtv.org
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OK.  There is definitely something wrong.
Tonight we have recorded about 3 hours of TV and after that...

- Top is currently showing 124Mb free (on a 6 GB system).
- Mythtv web is still drawing the 'listings' screen some 10 minutes 
after I clicked 'listings'.
- And the FE is still attempting to to draw the 'Watch Recordings' 
screen (only 60 recordings) some 8 minutes after I selected it.

The FE log keeps saying

Jul  6 21:58:05 XXXX mythfrontend[6742]: C PlaybackBoxHelper 
mythcorecontext.cpp:1154 (CheckProtoVersion) Protocol version check 
failure.#012#011#011#011The response to MYTH_PROTO_VERSION was 
empty.#012#011#011#011This happens when the backend is too busy to 
respond,#012#011#011#011or has deadlocked in due to bugs or hardware failure

The BE log doesn't seem to be saying anything exceptional - just the 
usual HouseKeeping and autoexpire messages.

None of the other log files in /var/log/mythtv have been updated recently.

Any suggestions as to where I should look for the problem?

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