[vdr] Vdr or driver performance dropout

[Stefan Huelswitt]

On 01 Feb 2007 Reinhard Nissl <rnissl at gmx.de> wrote:

> Heikki Manninen wrote:
> 
>>> I've noticed that earlier when I was using PIII 550 MHz and vdr 1.3.22 
>>> (or something about) I made a test by recording nine channels 
>>> simultaneously and watching a recording at the same time. I remember 
>>> there seemed to be no trouble doing it. Now when I have vdr 1.4.4 after 
>>> fourth recording starts vdr becomes sluggish and there starts to come 
>>> errors on log:
>>> dvb-ttpci: warning: timeout waiting in LoadBitmap
>>> when pushing menu button. And ofcourse no menu appears or menu appears 
>>> only partly.
>> 
>> Exactly the same thing here and with the latest and the second latest
>> firmware. My FF 2.1 TT card starts to die after third simultaneous
>> recording. But then again, I think that budget cards are much better in
>> this area.
> 
> Most likely, it's me who has to be blamed. Around 1.3.27, cVideoRepacker
> was introduced which has an impact on CPU load. This could be a reason
> why the menu is slow when running several recordings at the same time.

I don't think that the problem is related to anything on VDR
side.

AFAIK the bandwidth from ARM to PCI bus is very limited on
full-featured cards. With 3 recordings being transfered to VDR
there is simply not enough bandwidth left for the OSD transfers.
Hence the LoadBitmap timeout.

I experience the problem since VDR introduced concurrent
recordings and I cannot believe that there is any VDR / firmware
combination which doesn't show this behaviour as it's IMO a
hardware limitation.

Budget cards doesn't have this limitation, they can transfer the
full transponder without problems.

Regards.

-- 
Stefan Huelswitt
s.huelswitt at gmx.de  | http://www.muempf.de/