Re: [Discuss-gnuradio] How to balance workload among cores? Laptop cannot keep up with the USRP2 data flow.

[Tom Rondeau]

On Thu, Sep 30, 2010 at 5:52 AM, Jorge Miguel <address@hidden> wrote:
> Hi !
>
> Eric, thanks for your advise. Some results here.
>
> I set my computer into "performance mode". At first sight nothing improves.
>
> With the example usrp2_fft.py I can low the decimation to 5 and the
> application works ok.
>
> As I said the FM modulator works ok by itself. The FM demodulator also works
> ok by itself. The problem is when I run both in the same flowgraph. I think
> it is not a problem of performance since my CPUs are not very work-loaded
> when my application is running.
>
> My problem is that changes, in the FM modulator, which I think they would
> increase performance (like increasing my 13 interpolation in the USRP and
> decreasing my software interpolation) make my receiver chain non-working
> (SSS messages) although the transmitter outputs a perfect FM signal.
>
> I do not understand these mesages since my CPUs are less than 15-20% used.
> However something is stopping the received data because I got a lot of
> dropped frames in my rx Ethernet interface (saw with ifconfig). I tried to
> increase the RX Ethernet buffer (sysctl -w net.core.rmem_max=XXXXX) but it
> didn't work. I also tried to set in my generated code the USRP source
> instance before the USRP sink but it didn't work neither.
>
> Could be any reason why by decreasing software computation (and Ethernet
> traffic as well) in the transmitter path affects the performance of the RX
> path?
>
> Many thanks,
> Jorge.

This doesn't sound like a performance issue. I think you're probably
looking at a sample rate mismatch somewhere.

Tom