<br><br><div class="gmail_quote">On Tue, May 17, 2011 at 11:49 AM, Steven Adeff <span dir="ltr"><<a href="mailto:adeffs.mythtv@gmail.com">adeffs.mythtv@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
On Fri, May 6, 2011 at 9:46 AM, Kenneth Emerson<br>
<div class="im"><<a href="mailto:kenneth.emerson@gmail.com">kenneth.emerson@gmail.com</a>> wrote:<br>
</div><div><div></div><div class="h5">> Last night I modified the routine RingBuffer.cpp<br>
> (method: RingBuffer::CalcReadAheadThresh) to always choose the largest read<br>
> block size. Whether this was a proper change or not it did seem to<br>
> eliminate the pauses I had been seeing. I watched approximately four hours<br>
> of recordings without any pausing of the video or audio. I will leave this<br>
> change in for a week to see if it has really solved the symptoms (if not the<br>
> problem). At that point I might open a ticket with the patch.<br>
> Here is the diff for anyone else brave enough to give it a try:<br>
> diff --git a/mythtv/libs/libmythtv/RingBuffer.cpp<br>
> b/mythtv/libs/libmythtv/RingBu<br>
> index 8b59616..d4613d6 100644<br>
> --- a/mythtv/libs/libmythtv/RingBuffer.cpp<br>
> +++ b/mythtv/libs/libmythtv/RingBuffer.cpp<br>
> @@ -816,7 +816,10 @@ void RingBuffer::CalcReadAheadThresh(void)<br>
> rbs = (estbitrate > 5000) ? KB128 : rbs;<br>
> rbs = (estbitrate > 9000) ? KB256 : rbs;<br>
> rbs = (estbitrate > 18000) ? KB512 : rbs;<br>
> - readblocksize = max(rbs,readblocksize);<br>
> + // readblocksize = max(rbs,readblocksize); Ticket #8706:<br>
> 8706_debug.diff<br>
> + // Try to maximize readahead buffer. By KRE 05/04/2011<br>
> + rbs = KB512;<br>
> + readblocksize = rbs;<br>
> // minumum seconds of buffering before allowing read<br>
> float secs_min = 0.25;<br>
> Regards,<br>
> Ken E.<br>
<br>
</div></div>Ken, any word on how the patch worked out after a week of use?<br>
<div class="im"><br></div></blockquote><div>Unfortunately, this patch provided no relief. I have since backed out the change. I haven't been diligent in trying to correlate all of the pauses to external events, but the ones that I have chased down seem to align with other commenters in this thread. I definitely see pauses when recordings start/stop in the backend. I also see pauses when auto-expire occurs and files get deleted as well as when the preview image is being constructed. I do have the WD green drives, but I checked the SMART parameters for head parking and that is not the issue (slightly more head parks than power cycles and < 100 for three year old drives).</div>
<div><br></div><div>I still believe that something has changed as this wasn't a problem until sometime in .24-fixes (guessing within the last three months). Someone in this thread suggested going back to when .24 was forked off (last db update). Kenni and Jean-Yves both seemed to have tried going backward and were not able to locate where the problem surfaced (thinking it was pre .24 release).</div>
<div><br></div><div>I am on the verge of upgrading to 0.25 head hoping that most of the core changes for the 0.25 release have been made and that head is somewhat stable as this is the family's only DVR. It also might be useful if people who are seeing this problem report their configuration to see if there is any commonality in hardware and/or software. I am assuming that not everyone is experiencing this problem. So I will start:</div>
<div><br></div><div>Hardware:</div><div><br></div><div> Motherboard: <span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "><font class="Apple-style-span" face="verdana, sans-serif">P5K</font><font class="Apple-style-span" face="tahoma, sans-serif">-E/WIFI-AP LGA 775</font></span></div>
<div><font class="Apple-style-span" face="tahoma, sans-serif"><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "> CPU: </span><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; ">Core 2 Quad Q6600 Kentsfield 2.4GHz</span></font></div>
<div><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "><font class="Apple-style-span" face="tahoma, sans-serif"> Memory: 4GB DDR2 1066</font></span></div><div><font class="Apple-style-span" face="tahoma, sans-serif"><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "> Disk: 4 x </span><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; ">Western Digital Caviar Green WD10EACS 1TB SATA 3.0Gb/s (sda/b/c/d)</span></font></div>
<div><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "><font class="Apple-style-span" face="tahoma, sans-serif"> 1 x Western Digital WD5000KS 500GB SATA (sdf)</font></span></div>
<div><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "><font class="Apple-style-span" face="tahoma, sans-serif"> Video:</font></span></div><div><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "><font class="Apple-style-span" face="tahoma, sans-serif"> TV: Hauppauge HVR-1800 PCIe</font></span></div>
<div><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "><font class="Apple-style-span" face="tahoma, sans-serif"> Hauppauge PVR-250 PCI</font></span></div><div><span class="Apple-style-span" style="color: rgb(58, 58, 58); font-size: 12px; line-height: 20px; "><font class="Apple-style-span" face="tahoma, sans-serif"> Hauppauge PVR-350 PCI</font></span></div>
<meta http-equiv="content-type" content="text/html; charset=utf-8"><meta http-equiv="content-type" content="text/html; charset=utf-8"><meta http-equiv="content-type" content="text/html; charset=utf-8"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">
HDHR dual tuner<br></div></blockquote><div> Hauppauge HDPVR v 0x12</div><div><br></div><div>Software</div><div><br></div><div> OS: Ubuntu 10.04.02 LTS (32 bit)</div><div> Kernel: 2.6.32-31-generic #61-Ubuntu SMP</div>
<div> Other packages:</div><div> exim4 mail server</div><div> apache2 web server</div><div> samba v3.4.7</div><div> smartd v5.38</div><div> all mythtv scripts run by cron between 3am and 5am except for mythfilldatabase and mythcal which are run back-to-back between 5pm and 6pm.</div>
<div><br></div><div> MythTV combined FE/BE (no other computers)</div><div> Drive partition:</div><div> sda1/sdb1/sdc1/sdd1 -> RAID1 boot ext3</div><div> sda2/sdb2/sdc2/sdd2 -> RAID1 root ext3</div><div>
sda3/sdb3/sdc3/sdd3 -> RAID1 swap</div><div> sda4/sdb4/sdc4/sdd4 -> RAID5 LVM xfs (recordings)</div><div> sdf1 -> mysql database</div><div><br></div><div> mythfrontend running from xinit and gnome</div>
<div> mythbackend running with debug v0.24.1-1-g347cd24-dirty (in the process of removing all edits)</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div class="im">-- Ken E.</div></blockquote></div>