[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