[linux-dvb] Re: datarates: any experiences?

[Bart De Gruyter <bartdg@pobox.com>]

Bart De Gruyter wrote:
>
> > return value of netif_rx()
>
> just to let you know that I implemented this suggestion
> here locally and come to the following conclusion:
> netif_rx never returns high congestion or dropped
> packets so all packets are succesfully delivered to
> the upper network layers.
> 
> I also set the skb->ip_summed to CHECKSUM_UNNECESSARY
> to have a look if maybe the packets were thrown away
> in checksum calculations but they weren't. So it's
> still a mystery why the linux tcp/ip stack throws
> away the exact same packets that come in perfectly via
> the eth0 and eth1 interface but not via the dvb0_0
> interface while the driver is doing the job perfectly.
> 


forget all the previous remarks about return values of
netif_rx() and comments I made

Today we have succesfully transmitted a 49 Mb file
with UDP (adding FEC in the transmission) at a speed
of 57 Mbit/s. We use the NOVA card with this
tuner: BSRU6-502A

The key that gave us the possibility to receive at
this high speed was to set the SO_RCVBUF to
1Mb in the receiving udp socket.

Although this was not necessary for transmissions
via ethernet (with the same software and setup), it
is needed if you want to transmit something via dvb
and receive it with the nova card at speeds higher
than +-25 Mbit/s on linux and +- 10 Mbit/s in w2k.

Both the w2k professional and linux machines are able
to receive all the data at 57 Mbit/s speed.

The hauppauge nova card thus performs much better than
advertised.

greetings,

Bart De Gruyter



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