[mythtv-users] TCP performance issues

Kevin Ross kevin at familyross.net
Tue Sep 21 00:22:32 UTC 2010

  On 09/19/2010 06:16 AM, Eloy Paris wrote:
> Hello,
> I'm running up-to-date 0.23-fixes and after moving my frontend to
> Mythbuntu (it was running Debian and 0.23-fixes before) I started to
> experience playback issues that I did not experience before. The exact
> problem I am seeing are:
> - It takes a few seconds (about 5) for a recorded show to start playing.
> When I was running Debian, starting to play a show was a lot more
> quicker.
> - When the show starts to play there is stuttering for the first 2 or
> 3 seconds, like if the frontend is still filling up internal buffers.
> Stuttering stops after the initial few seconds and playback then
> proceeds normally. I did not experience this behavior when the frontend
> was running Debian.
> - Perhaps the most significant issue is that skipping forward (the
> default; 30 seconds?) or backward (the default, 10 seconds?) takes a
> long time (between 3 and 4 seconds) and the frotend seems to freeze
> during this time. I did not experience this behavior when the frontend
> was running Debian either
> To me it is puzzling that I did not experience this problem when the
> frontend was running Debian (and the corresponding mythtv packages from
> Christian Marillat). Furthermore, the machine is diskless, and because
> of this, the kernel used is exactly the same, i.e. I didn't even rebuild
> it; I built it when the machine was running Debian and kept it for the
> Mythbuntu install.
> One final data point is that I configured the frontend to directly
> access the recordings via NFS instead of using the Myth protocol and
> connecting to the backend and all the problems went away -- immediate
> playback, immediate response to skipping forward/backward, and no
> stuttering the first few seconds of playback. To add to the mystery, NFS
> is also using TCP, just as the Myth protocol.
> Any thoughts, ideas, or suggestions?
> Thanks in advance.
> Eloy Paris.-

When I let it stream using the Myth protocol, I would get similar issues 
you are getting.  Using NFS everything is much better.

I'm running Debian, so I don't think it's a Debian-vs-Mythbuntu issue.

-- Kevin

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