[mythtv] Re: Solving my performance problems...

[Bruce Markey]

Mark Frey wrote:
...
> 1. I need someone to test on a setup with frontend machine != backend
> machine and let me know if they have any problems (worse performance,
> segfaults, etc.) I've added a couple of VERBOSE, VB_GENERAL messages to note
> where timeouts occur in the new scheme, so let me know if you see any of the
> following messages:
>  Frontend messages:
>      "socket error in RemoteFile::Read()"
>      "No response from control socket in RemoteFile::Read()"
>      "RemoteFile::Read() failed in RingBuffer::safe_read()"
> Backend messages:
>      "..end WriteBlock with false, error = %1"
>      "****Aborting WriteBlock"
> I'll remove these messages (or change them to VB_NETWORK as appropriate)
> when/if I submit this patch.

On the very first attempt, it paused several times and failed
within 20sec.

Frontend:

2003-12-17 18:05:39 Connecting to backend server: 192.168.0.35:6543 (try 1 of 1)
2003-12-17 18:05:44 Opening OSS audio device '/dev/dsp'.
2003-12-17 18:05:44 Using XV port 111
2003-12-17 18:05:44 Changing from None to WatchingPreRecorded
2003-12-17 18:05:50 prebuffering pause
2003-12-17 18:05:53 prebuffering pause
2003-12-17 18:05:54 prebuffering pause
2003-12-17 18:05:56 prebuffering pause
2003-12-17 18:05:57 prebuffering pause
2003-12-17 18:05:59 prebuffering pause
2003-12-17 18:06:00 prebuffering pause
2003-12-17 18:06:03 prebuffering pause
2003-12-17 18:06:03 RemoteFile::Read() failed in RingBuffer::safe_read()
2003-12-17 18:06:04 Changing from WatchingPreRecorded to None
2003-12-17 18:06:04 Changing from None to None

Backend:

2003-12-17 18:05:43 MainServer::HandleAnnounce Playback
2003-12-17 18:05:43 adding: nordtv as a client (events: 0)
2003-12-17 18:05:43 MainServer::HandleAnnounce FileTransfer
2003-12-17 18:05:43 adding: nordtv as a remote file transfer
2003-12-17 18:06:03 ****Aborting WriteBlock

Other attempts did better but I haven't been able to run for
more than a couple minutes without playback exiting on a false
EOF.

I also noticed that seeks are considerably slower so I did
a test to see how long it takes to skip forward in a one hour
remote file. The fast forward amount was set to 30 so there
would be about 120 seek to get through the file. However, on
four attempts I never got all the way through without a Read()
failed in RingBuffer::safe_read(). The closest I got was 54min
in 1:46. Without the patch it took 49 seconds to make it to
the end of the file so seeks with the patch take more than
twice as long.

--  bjm