[linux-dvb] DVB API update

Wolfgang Wegner wolfgang at leila.ping.de
Tue Sep 18 13:38:26 CEST 2007


On Tue, Sep 18, 2007 at 02:26:13PM +0200, Georg Acher wrote:
> The Reelbox (with the 300MHz) has up to 4 tuners, the NetCeiver can have up
> to 6 tuners (max 40Mbyte/s input rate). I did a lot of profiling
> (oprofile/gprof) on the Geode, so I think I know what multi demods can "do"
> with the system.
> 
> But the real performance problems appear in user space, not in the kernel.
> Eg. vdr uses two additional ringbuffers to move the TS around (10% for one
> channel). vdr's EPG parsing on the ARD transponder can take initially more
> than 40% CPU (on the Geode). Repacking a simple SDTV-Stream with 6Mbits/s
> into PES takes another 15-20%. Compared to that, the DVB subsystem is
> neglectable... With faster CPUs (better memory system, larger caches) I
> expect the impact to be even less.

Thanks for the numbers, Georg!

That was all my previous posting was about, so now we know these facts,
my objections can be ignored, I think.

Regards,
Wolfgang




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