[vdr] Re: [PATCH] Reduce CPU usage during playback

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Sascha Volkenandt wrote:
> 
> At Freitag, 13. Juni 2003 19:15 Jon Burgess wrote:
> > Here is an experimental two line patch which dramatically reduces the
> > CPU load of VDR during playback (not live video). For me, this reduces
> > the CPU load for video playback from around 40% to <10%. The CPU load
> > for audio drops even more, from around 30% to <1%.
> 
> I've encountered this behaviour ONLY when replaying MPEG1-Files put into the
> VDR structure with correct index.vdr (which comes from a modifies genindex
> which I think is not available yet for creating correct MPEG1 indices). The
> following patch solved this issue for me.

I wonder why this is only with MPEG1 files...?

Could you provide such a file (actually a complete VDR recording directory)
of some 10MB size, so I could try to reproduce this here?

> Remarkable is, that this patch applies at a completely different location
> (Poller GETS data, but no playFrame is available afterwards)

The cPoller in cDvbPlayer::Action() doesn't poll the _read_ side, but rather
the _write_ side (i.e. it checks whether the DVB device is able to take new
data). So is it not the least surprising the DevicePoll() returns true but
playFrame is NULL.

> and drops CPU
> usage from about 50% (Duron 900MHz) to the usual 1-2% again. I've had no
> problems with VDR recordings so far!

Amazing. There must be something totally different with MPEG1 files.

> Anyone with a little more time than me (too much going on currently) who
> might want to investigate this?!
> 
> @Klaus: Or would you include this one right away? It seems that waiting a
> microsecond when no work has to be done is a common practise in VDR :-)))

I'd like to test this myself with an actual MPEG1 file first.
So please, if you can, let me know where to download one (or use
our upload facility at http://www.cadsoft.de/upload.htm - don't worry,
I'll be the only one to see the uploaded file).

Klaus
-- 
_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10
CadSoft Computer GmbH                   Fax:   +49-8635-6989-40
Hofmark 2                               Email:   kls@cadsoft.de
D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de
_______________________________________________________________


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