Re: [Q]: any DVB-S2 card which is 45MS/s capable?

[Emmanuel <eallaud@gmail.com>]

Marko Ristola a écrit :
>
> Hi.
>
> I have written some Mantis bandwidth related
> DMA transfer optimizations on June/July this year.
> They are now waiting for approval by Manu Abraham.
>
> Those reduce CPU pressure, increasing the bandwidth
> that can be received from the DVB card. 45MS/s bandwidth
> support will surely benefit from those patches.
>
> Main features:
> 1. Do one CPU interrupt per 16KB data instead per 4KB data.
> My implementation benefits only Mantis cards.
> https://patchwork.kernel.org/patch/107036/
>
> 2. Remove unnecessary big CPU overhead, when data is delivered
> from the DVB card's DMA buffer into Linux kernel's DVB subsystem.
> Number 2 reduces the CPU pressure by almost 50%.
> This implementation benefits many other Linux supported DVB cards too.
> http://patchwork.kernel.org/patch/108274/
>
> Those helped with my older single CPU Core computer with 256-QAM,
> delivering HDTV channel into the network and watching the
> HDTV channel with a faster computer.
>
> The performance bottlenecks could be seen on the
> command line with "perf top".
>
> I had to increase PCI bus latency setting into 64 too from the BIOS.
> Moving DVB device into separate IRQ line with Ethernet card helped too,
> because Ethernet card did an interrupt per ethernet packet.
>
> So if the hardware can deliver 45MS/s data fast enough, software side 
> can be optimized up
> to some point. My patches contain the most easy major optimizations 
> that I found.
> If you can test some of those patches, it might help to get them into 
> Linux kernel
> faster.
>
> Best regards,
> Marko Ristola
>
OK these optimizations look like a step into the good direction. I guess 
what is also missing is a tuner which can handle that in DVB-S2, which 
does not seem obvious. The mantis card  can do that?
Thx
Bye
Manu