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Help with a different jitter problem.
http://forum.linhes.org/viewtopic.php?f=6&t=2933		 Page 1 of 1
Author:  nbdwt73 [ Sat Nov 20, 2004 5:05 pm ]
Post subject:  Help with a different jitter problem.
I have searched this forum and several others looking for a similar problem and solution to no avail... I am running Knoppmyth R4V5 and the system generally runs well (thanks to all for the help and input over the past year in making that happen) but for one annoying problem. It seems to be similar to the jitter problem that has been discussed repeatedly except that it is more like a jerk or pause every several seconds and only when viewing a show that is recording (time shifting) or when watching a recording while another is recording (same thing…). Now for the weird part… it doesn’t happen until several minutes into a recording (for the first 10 – 15 minutes it is fine) and then it happens until the recording function is complete. It is as if it pauses for some buffer write or caching…

I am running Knoppmyth R4V5 on a:

Compaq EVO 1.8 ghz,
160 gig Seagate (7200 rpm, 8mg buffer - only device on this controller),
512mg P133 SDRAM,
nVidia GeForce MX440,
Creative Labs SB Live,
Hauppauge capture card


I have been tweaking for weeks with no apparent effect. I have noticed a rare occurrence when watching live TV but not often. I have tried changing the software encoder image size from 480 X 480 to 640 X 480 ( and several in between) – no impact. I have added more memory - to 640 mg - nothing. A few more details – commercial flagging is off, CPU is running between 35% and 45% when recording and between 60% and 80% (usually between 65% and 70%) when recording and playing (see TOP data below).

Below is the HDPARM data

/dev/hda:
multcount = 16 (on)
IO_support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 1 (on)
readonly = 0 (off)
readahead = 8 (on)
geometry = 19457/255/63, sectors = 312581808, start = 0

and TOP data below:

top - 17:48:32 up 7:23, 3 users, load average: 1.59, 0.84, 1.03
Tasks: 96 total, 3 running, 93 sleeping, 0 stopped, 0 zombie
Cpu(s): 61.0% user, 39.0% system, 0.0% nice, 0.0% idle
Mem: 515472k total, 509968k used, 5504k free, 8476k buffers
Swap: 672832k total, 35460k used, 637372k free, 335936k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ Command
1643 mythtv 17 0 44792 37m 9736 R 39.9 7.4 14:26.45 mythbackend
1780 mythtv 15 0 100m 94m 29m R 26.5 18.7 0:08.27 mythfrontend
1779 mythtv 12 0 100m 94m 29m S 14.7 18.7 0:05.03 mythfrontend
1642 mythtv 9 0 44792 37m 9736 S 4.2 7.4 1:58.49 mythbackend
1641 mythtv 11 0 44792 37m 9736 S 2.6 7.4 0:11.92 mythbackend
1782 mythtv 9 0 100m 94m 29m S 2.2 18.7 0:00.66 mythfrontend
1783 root 16 0 1024 1024 804 R 2.2 0.2 0:00.41 top
1645 mythtv 9 0 44792 37m 9736 S 1.6 7.4 0:20.96 mythbackend
864 root 5 -10 116m 43m 14m S 1.3 8.6 1:20.28 XFree86
1053 mythtv 9 0 100m 94m 29m S 1.3 18.7 0:33.68 mythfrontend
754 mythtv 9 0 44792 37m 9736 S 0.6 7.4 0:04.01 mythbackend
4 root 9 0 0 0 0 S 0.3 0.0 0:01.83 kswapd
872 mythtv 9 0 44792 37m 9736 S 0.3 7.4 0:00.09 mythbackend
873 mythtv 9 0 44792 37m 9736 S 0.3 7.4 0:00.87 mythbackend
900 root 9 0 0 0 0 S 0.3 0.0 0:02.52 lirc_dev
1644 mythtv 9 0 44792 37m 9736 S 0.3 7.4 0:08.69 mythbackend
1 root 8 0 60 52 32 S 0.0 0.0 0:04.47 init
2 root 8 0 0 0 0 S 0.0 0.0 0:00.02 keventd
3 root 19 19 0 0 0 S 0.0 0.0 0:00.03 ksoftirqd_CPU0
5 root 9 0 0 0 0 S 0.0 0.0 0:00.00 bdflush
6 root 9 0 0 0 0 S 0.0 0.0 0:00.00 kupdated
8 root 9 0 0 0 0 S 0.0 0.0 0:00.14 kjournald
106 root 9 0 0 0 0 S 0.0 0.0 0:00.00 khubd
147 root 9 0 0 0 0 S 0.0 0.0 0:00.55 msp3410 [auto]
237 root 9 0 0 0 0 S 0.0 0.0 0:00.01 kjournald
339 root 9 0 700 584 584 S 0.0 0.1 0:00.09 pump
370 daemon 9 0 384 316 316 S 0.0 0.1 0:00.00 portmap
481 root 9 0 612 588 516 S 0.0 0.1 0:00.02 syslogd
496 root 9 0 1228 496 448 S 0.0 0.1 0:00.08 klogd
552 root 9 0 1912 956 936 S 0.0 0.2 0:00.05 apache
568 root 8 0 1948 1692 1024 S 0.0 0.3 0:00.12 cupsd
580 www-data 9 0 4940 2804 2788 S 0.0 0.5 0:00.14 apache
581 www-data 9 0 2896 2120 2120 S 0.0 0.4 0:00.00 apache
582 www-data 9 0 4380 2840 2784 S 0.0 0.6 0:00.09 apache
583 www-data 9 0 4976 4644 2780 S 0.0 0.9 0:00.15 apache
584 www-data 9 0 2884 2164 2052 S 0.0 0.4 0:00.01 apache
601 root 9 0 504 448 448 S 0.0 0.1 0:00.01 inetd
634 root 9 0 1268 1052 1052 S 0.0 0.2 0:00.02 mysqld_safe
674 mysql 9 0 7288 4496 2140 S 0.0 0.9 0:00.05 mysqld

I am out of ideas… Any suggestions? What additional information may help? Thanks again.
Author:  cesman [ Sat Nov 20, 2004 5:13 pm ]
Post subject: 
Is that 512 megs of PC-133? If so, while your board/processor may work fine with PC-133 it probably isn't optimal. That is the first place I'd start...
Author:  nbdwt73 [ Sat Nov 20, 2004 5:33 pm ]
Post subject: 
Thanks cesman... It is pc 133... Are you suggesting that I go to faster memory? I thought, given the motherboard is (or so it says) designed for PC 133 (I asssume the bus is operating at that speed) will faster memory be a significant benefit? What do you run?
Author:  cesman [ Sat Nov 20, 2004 7:37 pm ]
Post subject: 
I wrote what I thought would be the first place I'd start to look. Please re-read it. I don't think any 1.8 gig processor was designed w/ PC-133 in mind. I may be wrong, I don't pay as much attention to hardware as I use to... I run LinHES.
Author:  bugmenot [ Wed Jan 26, 2005 11:17 pm ]
Post subject: 
I had a very similar problem. My system(PII-450) was not able to keep up with the automatic commercial detection. Your system is faster, but I thought this might help.
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