[mythtv-users] Mythtv stuttering - help debugging
mythtv at corwyn.net
mythtv at corwyn.net
Wed Mar 18 22:24:05 UTC 2009
Environment:
I'm currently running mythtv-0.21-198.el5 on CentOS kernel
2.6.18-92.1.18.el5 with a Happtpauge pvr-350
I have a server that is frontend and backend, but I normally watch
myth using mvpmc on the Haupptpauge MediaMVP. The problem I see is
that after running for a while the video starts stuttering. the
buffer indicator on the mvpmc shows that the buffer isn't staying full.
the mvpmc code has a memory leak that can cause stuttering, but a
soft and hard reboot of the mediamvp only rarely resolves the
problem. A reboot of the server on the other hand tends to resolve
the problem for a few hours.
I've swapped out the network cable and switch that connects the two
devices. (although the NIC isn't reporting any errors) I've pondered
IRQ issues, nic driver issues, drive performance issues, heat issues
on the mvpmc. The system isn't running another recording, or
performing and tasks like transcoding/commercial flagging. However, I
think the problem is directly related to myth somehow.
If I'm in a stuttering state, I can exit the myth part of the mvpmc,
and view a mpg through the mvpmc with no problem, and a higher rate
(6 mpbs, where Myth tv is typically 4 mbps according to the mvpmc).
Exiting that video and going back to myth, and I'm immediately back
to stuttering.
So I think it's related somehow to myth (reboot of the server fixing
it, watching plain video sans myth through the mvpmc code works
fine). However, stopping and starting the mythbackend service and/or
the mysqld service also doesn't "reset" the problem
the only log event sin mythbackend.log are
2009-03-18 18:03:44.235 MainServer::HandleVersion - Client speaks
protocol version 8 but we speak 40!
2009-03-18 18:03:44.240 MainServer::HandleAnnounce Playback
2009-03-18 18:03:44.241 adding: 192.168.2.57 as a client (events: 0)
2009-03-18 18:03:44.243 MainServer::HandleAnnounce FileTransfer
2009-03-18 18:03:44.244 adding: 192.168.2.57 as a remote file transfer
Disk performance looks ok:
[root at glutton log]# hdparm -tT /dev/sdb
/dev/sdb:
Timing cached reads: 3860 MB in 2.00 seconds = 1929.88 MB/sec
Timing buffered disk reads: 230 MB in 3.02 seconds = 76.06 MB/sec
[root at glutton log]# hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 3756 MB in 2.00 seconds = 1877.72 MB/sec
Timing buffered disk reads: 228 MB in 3.01 seconds = 75.74 MB/sec
top results are equally not informative:
top - 18:25:33 up 18:03, 1 user, load average: 0.10, 0.12, 0.09
Tasks: 115 total, 1 running, 114 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.3%us, 1.5%sy, 0.0%ni, 98.2%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 1800232k total, 1545056k used, 255176k free, 43216k buffers
Swap: 2024180k total, 124k used, 2024056k free, 1051948k cached
and ethtool reports 100 MB/FD (it was GB/FD until I swapped out the
switch, no difference)
the my.cnf settings match what's suggested in the MYTHTV HOWTO for
optimizing performance http://www.mythtv.org/wiki/Optimizing_Performance
Any pointers on where else I can look to debug the problem?
Thx.
Rick
Rick Steeves
http://www.sinister.net
"The journey is the destination"
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