[mythtv-users] Pausing issues
Robert Dege
livemotion at gmail.com
Mon Dec 31 02:24:26 UTC 2012
@Josu:
I was finally able to work on, and fix the pausing problem. Modifying the
following mysql variables fixed the pausing problem:
[mysqld]
tmp_table_size = 67108864
max_heap_table_size = 67108864
query_cache_limit = 8388608
query_cache_size = 33554432
In addition, I also setup /tmp as tmpfs, whereas it was originally part of
the / partition. This did not contribute as part of the solution, but
seemed more like a mysql performance tweak
@Curtis:
I ran into severe lag issues with mysql and ext4, so I downgraded the file
system on /var to ext3 with noatime. However, despite that setup, I was
still experiencing the pausing issues.
-Rob
On Sat, Dec 1, 2012 at 10:09 AM, Curtis <curtis.porter at gmail.com> wrote:
> 2012/11/30 Robert Dege <livemotion at gmail.com>:
>>
>>> Whenever I watch LiveTV, or watch a recording in progress, about 85% of
>>> the
>>> time, the playback will pause for about half a sec, and then resume.
>>> There's no notification on the screen, or any picture distortion. This
>>> pause occurs every 5 to 7 seconds. At first, I thought that the mythbox
>>> was
>>> being overloaded (I have an HD Prime that can record up to 3 channels at
>>> once onto two physical hard drives). However, I noticed that I can
>>> watch an
>>> old show with no interruptions while all 3 tuners are active. I also
>>> discovered that the pausing issue occur even if only one tuner is active,
>>> and I'm watching that recording in progress.
>>>
>>> I'm not exactly sure how I should go about troubleshooting this problem,
>>> so
>>> any suggestions are appreciated.
>>>
>>
> I recently experienced a very similar issue, and running iotop on the
> backend showed that during the playback pauses was high IO by the process
> "[jbd2/sdb1-8]". This is the journaling block device for my ext4 root
> filesystem. Setting the "noatime" mount option on the root filesystem
> appears to have resolved the problem. Since my recordings are written to a
> different filesystem, I suspect this was related to mysql activity.
>
> Good luck,
>
> Curtis
>
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