[mythtv-users] Sorry, another Prebuffering Pause...

[Alex Masidlover]

Hi,

I've been through the troubleshooting page and searched many threads on 
this list, but can't find any solution to my pre-buffering pauses. My 
set-up is a Core2 frontend with Nvidia graphics and a backend with Intel 
E2140 processor (dual core), both are Asus motherboards. Network is 
wired 100mbps.

This is the kind of thing I get:

2011-02-05 20:41:25.864 
RingBuf(myth://192.168.0.152:6543/1001_20110203210000.mpg): Waited 1.0 
seconds for data to become available...
2011-02-05 20:41:26.169 NVP(1): prebuffering pause

I've tried NFS and streamed set-ups.

I did have the recordings on a USB drive, but have since moved them to a 
SATA exclusively for recordings.

Load on frontend is very low when stuttering occurs.

Load on backend is not massive, but is very odd:

top - 20:43:56 up 31 days,  3:46,  1 user,  load average: 1.55, 1.43, 1.37
Tasks: 156 total,   1 running, 155 sleeping,   0 stopped,   0 zombie
Cpu0  :  0.7%us,  0.3%sy,  0.0%ni, 98.7%id,  0.0%wa,  0.0%hi,  0.3%si,  
0.0%st
Cpu1  :  0.7%us,  0.0%sy,  0.0%ni, 99.3%id,  0.0%wa,  0.0%hi,  0.0%si,  
0.0%st
Mem:   1023716k total,   872468k used,   151248k free,   108380k buffers
Swap:  1028156k total,    17024k used,  1011132k free,   488752k cached

   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  8943 mythtv    20   0  319m  56m 5264 S    4  5.6 410:32.90 mythbackend
  8577 mysql     20   0  205m  52m 4980 S    1  5.3 180:21.70 mysqld
  5732 ldap      20   0  129m  22m 2176 S    0  2.2   3:52.37 slapd
12536 asterisk  20   0 39000  17m 4196 S    0  1.7   0:00.81 apache2
[snip]

What strikes me as odd is the load average is 1-1.5 while the stuttering 
is occuring, but both CPUs are 90% idle (or more).

dmesg is free of any new messages since boot up (I wondered about i/o 
reads or the like).

I'm currently installing munin to do some more in depth monitoring, but 
wondered 2 things:

1) Am I on the right track in assuming that the server is not supplying 
data fast enough?

2) Is Munin the best way to track down the culprit - would there be 
easier/quicker ways?

Thanks in advance,

Alex