[linux-dvb] Re: Driver CPU requirements?

[Holger Waechtler <holger@convergence.de>]

Lauri Pesonen wrote:
> Hi,
> 
> I was just updating my Gentoo Linux based VDR box and noticed that
> compiling new software raised the system load to 2.5 and above.
> Eventually the system over heated, I guess, since the compiler exited
> with Sig11. 

Sig11 is a Segmentation Fault, this should never happen and means either 
a compiler bug or that your system was running out of memory but the 
compiler did not checked the malloc/calloc return value.


>  I killed VDR and unloaded the driver and retried. The system load stayed
> below 1.5 and all compilations were finished ok. 
> 
> So I'm wondering is the driver enforcing a lot of context switches,
> which, I guess, would explain the high load during compiling, or am I
> just experiencing some weird anomaly?

For HighEnd-Cards (those with the onboard MPEG decoder) the system load 
in normal use with a stable RF signal should stay near zero, only the 
ARM recovery thread and the frontend recovery thread have to check the 
hardware status sometimes.

When the signal gets lost the zigzag scan will start and cause some load.

If you use a NOVA- or Budget then demultiplexing and MPEG-decoding is 
done in software, so the CPU load will be higher.

Holger



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