[vdr] Re: Transfer mode

[Andreas Schultz <aschultz@cs.uni-magdeburg.de>]

Hi all,

Klaus Schmidinger wrote:
> Tilo Renkl wrote:
> 
>>Hi List,
>>
>>can anybody tell me, why CPU usage of my VDR in transfermode is between 60
>>an 95 % (Athlon XP 1800+),
>>but when timeshifting with an offset of 2-4 seconds CPU usage is normal ?
> 
> 
> Your machine is *way* faster than the one VDR was originally developed on.
> Maybe the usleep(1) call in cTransferBuffer::Output() (in dvbapi.c) should be
> changed to a somewhat higher value. Try usleep(100) or usleep(1000). Maybe
> you'll need even more.
> 
> I'll need to make this use mutexes to work without excessive CPU usage
> on fast machines...

I had a look at some old RingBuffer changes i did for the DVD stuff. 
Those changes where mostly related to the PlayBuffer stuff. I have 
updated them and also did some modfications to the Record- and 
TransferBuffers. The main purpose of the patch, is to get rid of any 
busy wait type loops in dvbapi.c.
You can find a patch for 1.0.0-pre3 that changes the complete buffer 
locking and syncing handling at:
http://www.cs.uni-magdeburg.de/~aschultz/dvd/vdr-1.0.0pre3-sync.diff.bz2

The above patch works for me, but i have only one card. So, only 
recording is tested. But TransferMode should be almost the same.

Also, load on my 1GHz Duron is slightly higher than before, i believe 
that this is due to the changed sheduling semantics and will actually 
reduce latencies in VDR and therefore also show some benefits on slow 
systems.

Andreas

> 
> Klaus