Re: [Discuss-gnuradio] Setting buffer size when using UHD

[Josh Blum]

On 09/21/2010 01:30 AM, Per Zetterberg wrote:
> I read the page you refer to but I don't understand. Is this correct ?
>
> uhd::device_addr_t dev_addr;
> dev_addr["addr"] = "192.168.10.11 192.168.20.11";
> dev_addr["addr"] = "192.168.10.11 192.168.20.11";
> dev_addr["recv_buff_size"] = "1e4";
> d_mdev=uhd::usrp::mimo_usrp::make(dev_addr);

That should work, however, that is a very small buffer. Expect overflow.

> > If this is linux, I recommend setting sysctl and letting UHD
> > automatically pick the size.
> >
> > sudo sysctl -w net.core.rmem_max=50000000
> Yes. But then I need to do change this value when depending on which 
> application I about to run or ... ?

50MB is half a second of buffering at full rate. The default behavior of 
the UHD is to resize recv buffers to 50 MB. I think that is sufficient 
for most applications.

-Josh