[mythtv-users] Performance issue on 0.24-fixes - Playback stalls when a recording starts/ends

Mon Mar 21 09:00:11 UTC 2011

Zitat von Martin Andersen <ma2010.list at gmail.com>: 

> Hi list
>
> I've just upgraded from 0.23 to 0.24-fixes, but I'm having problems with playback which I didn't have on 0.23. Playback often pauses for a second or two - apparently when a recording start or stop.
>
> I have a fairly capable Core i5 as a backend and a ION-based frontend on a gigabit network. The backend log doesn't give any errors and the frontend gives me:
> 2011-03-16 17:06:03.446 VDPAU: Added 2 output surfaces (total 4, max 4)
> 2011-03-16 17:30:01.611 ALSA, Error: WriteAudio: buffer underrun
> 2011-03-16 17:30:01.881 Player(1): Waited 100ms for video buffers AAAAAAAAAAAAAaALL
> 2011-03-16 17:30:01.887 Player(1): Waited 100ms for video buffers AAAAAAAAAAAAAaALL
> 2011-03-16 17:30:01.898 Player(1): Waited 100ms for video buffers AAAAAAAAAAAAAaALL
> 2011-03-16 17:30:01.903 Player(1): Waited 100ms for video buffers AAAAAAAAAAAAAaALL
> 2011-03-16 17:30:02.008 Player(1): Waited 100ms for video buffers AAAAAAAAAAAAAaALL
> 2011-03-16 17:30:02.024 Player(1): Waited 100ms for video buffers AAAAAAAAAAAAAaALL
> 2011-03-16 17:30:02.666 RingBuf(myth://192.168.1.10:6543/1000_20110316173000.mpg) Warning: Not starting read ahead thread, already running
> 2011-03-16 17:30:02.694 Player(1): Forcing decode extra audio option on (Video method requires it).
> 2011-03-16 17:30:02.775 AFD Warning: ScanATSCCaptionStreams() called with no PMT
> 2011-03-16 17:30:02.775 AFD: Opened codec 0x7fee30e62c30, id(MPEG2VIDEO) type(Video)
> 2011-03-16 17:30:02.775 AFD: codec MP2 has 2 channels
> 2011-03-16 17:30:02.775 AFD: Opened codec 0x7fee3009def0, id(MP2) type(Audio)
> 2011-03-16 17:30:02.799 AFD: Resetting byte context eof (livetv 1 was eof 0)
> 2011-03-16 17:30:02.889 [mpegvideo_vdpau @ 0x7fee57f515a0]warning: first frame is no keyframe
> 2011-03-16 17:30:03.032 [mpegvideo_vdpau @ 0x7fee57f515a0]warning: first frame is no keyframe
>
> MythTV Version   : v0.24-211-g785ea1b
> MythTV Branch    : fixes/0.24
> Network Protocol : 63
> Library API      : 0.24.20101129-1
> QT Version       : 4.6.2
>
> I've tried to search the list, and it seems like quite a few users are affected by the issue:
> http://www.gossamer-threads.com/lists/mythtv/users/474214#474214
>
> Does a bug report exist or has anyone identified/fixed the issue?
>
> Does anyone know if the issue is the same in trunk?
>
> Thanks

Since no one replied to this yet, I'd like to confirm that I see this issue too. Though not only when another recording starts and stops, but also when a new show starts during LiveTV. But worst of all is when running mythfilldatabase.

The culprit is marking of first and last showings. Here's some log of an mythfilldatabase run:

2011-03-20 18:57:39.038 Using runtime prefix = /usr
2011-03-20 18:57:39.038 Using configuration directory = /home/jan/.mythtv
2011-03-20 18:57:39.060 Empty LocalHostName.
2011-03-20 18:57:39.060 Using localhost value of htpc
2011-03-20 18:57:39.102 New DB connection, total: 1
2011-03-20 18:57:39.112 Connected to database 'mythconverg' at host: localhost
2011-03-20 18:57:39.132 Closing DB connection named 'DBManager0'
2011-03-20 18:57:39.133 Connected to database 'mythconverg' at host: localhost
2011-03-20 18:57:39.134 Current locale DE_DE
2011-03-20 18:57:39.156 Reading locale defaults from /usr/share/mythtv//locales/de_de.xml
2011-03-20 18:57:39.204 Loading de translation for module mythfrontend
2011-03-20 18:57:39.206 Current MythTV Schema Version (DBSchemaVer): 1264
2011-03-20 18:57:39.208 New DB connection, total: 2
2011-03-20 18:57:39.209 Connected to database 'mythconverg' at host: localhost
2011-03-20 18:57:39.976 Updating source #1 (EPG) with grabber tv_grab_eu_epgdata
2011-03-20 18:57:39.976 Found 49 channels for source 1 which use grabber
2011-03-20 18:57:40.452 Grabber has capabilities: baseline manualconfig tkconfig apiconfig cache preferredmethod 
2011-03-20 18:57:40.903 Grabber prefers method: allatonce
2011-03-20 18:57:40.903 New DB connection, total: 3
2011-03-20 18:57:40.903 Connected to database 'mythconverg' at host: localhost
2011-03-20 18:57:40.904 XMLTV config file is: /home/jan/.mythtv/EPG.xmltv
2011-03-20 18:57:40.904 New DB connection, total: 4
2011-03-20 18:57:40.904 Connected to database 'mythconverg' at host: localhost
2011-03-20 19:52:59.832 New DB connection, total: 5
2011-03-20 19:52:59.833 Connected to database 'mythconverg' at host: localhost
2011-03-20 19:53:07.268 IconData: Updating icons for sourceid: 1
2011-03-20 19:53:11.190 New DB connection, total: 6
2011-03-20 19:53:11.191 Connected to database 'mythconverg' at host: localhost
2011-03-20 19:55:32.778 Updated programs: 12865 Unchanged programs: 19128
2011-03-20 19:55:35.055 Updating source #2 (EPG 2) with grabber tv_grab_eu_epgdata
2011-03-20 19:55:35.055 Found 23 channels for source 2 which use grabber
2011-03-20 19:55:37.083 Grabber has capabilities: baseline manualconfig tkconfig apiconfig cache preferredmethod 
2011-03-20 19:55:37.662 Grabber prefers method: allatonce
2011-03-20 19:55:37.663 XMLTV config file is: /home/jan/.mythtv/EPG 2.xmltv
2011-03-20 20:18:15.764 IconData: Updating icons for sourceid: 2
2011-03-20 20:19:55.193 Updated programs: 6791 Unchanged programs: 9135
2011-03-20 20:19:55.646 Data fetching complete.
2011-03-20 20:19:55.646 Adjusting program database end times.
2011-03-20 20:19:57.356     8 replacements made
2011-03-20 20:19:57.356 Marking generic episodes.
2011-03-20 20:19:59.388     Found 6889
2011-03-20 20:19:59.388 Fudging non-unique programids with multiple parts.
2011-03-20 20:19:59.655     Found 0
2011-03-20 20:19:59.655 Marking repeats.
2011-03-20 20:20:00.229     Found 0
2011-03-20 20:20:00.229 Unmarking new episode rebroadcast repeats.
2011-03-20 20:20:00.230     Found 0
2011-03-20 20:20:10.740 Marking episode first showings.
2011-03-20 20:38:06.190     Found 33633
2011-03-20 20:38:06.190 Marking episode last showings.
2011-03-20 20:55:14.959     Found 33633
2011-03-20 20:55:15.051 
===============================================================
| Attempting to contact the master backend for rescheduling.  |
| If the master is not running, rescheduling will happen when |
| the master backend is restarted.                            |
===============================================================
2011-03-20 20:55:15.288 MythCoreContext: Connecting to backend server: htpc.wg.de:6543 (try 1 of 1)
2011-03-20 20:55:16.664 Using protocol version 63
2011-03-20 20:55:16.765 Received a remote 'Clear Cache' request
2011-03-20 20:55:17.766 mythfilldatabase run complete.
2011-03-20 20:55:17.878 DataDirect: Deleting temporary files

Please take a look at the insane timestamps. The first gaps are fine. But during the "Marking episode first/last showings." gaps, the machine almost grinds to a halt due to massive disc I/O, and a huge load. Munin shows really high peaks in MySQL usage during that time.

This also started with 0.24 for me. Most times I don't notice, because I already moved the EPG update to a time of day when I don't watch TV. 

Jan.

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