Re: [Discuss-gnuradio] Overrun when there shouldn't be

[Eric Blossom]

On Mon, Feb 09, 2009 at 11:34:17PM -0800, Chris Stankevitz wrote:
> Johnathan Corgan wrote:
> > On Mon, Feb 9, 2009 at 7:07 PM, Chris Stankevitz <address@hidden> wrote:
> > 
> >> I wrote a c++ program that grabs data from the USRP in an infinite loop
> >> and does nothing with it.  It overruns.  Can anyone help me figure out why?
> > 
> > Can you try it without the call to set_format()?
> 
> Johnathan,
> 
> Even without the call to set_format, I still get overruns.  I also made
> some other changes:
> 
> 1) Original code (overruns)
> 2) 1) minus set_format (overruns)
> 3) 2) with NumChannels==1 (no overruns)
> 4) 3) with DecimRate==32 vs 16 (no overruns)
> 
> Test 3 not overrunning was no surprise since it's cuts the data in half.
>  However, Test 4 note overrunning was a huge surprise because Test 4
> pumps the same amount of data as Test 2 which does overrun.
> 
> Question: Why would 2 channels at 4MHz overrun while 1 channel at 8MHz
> not overrun?
> 
> Chris

Chris,

Try this:

#include <gr_realtime.h>

  ...

  gr_enable_realtime_scheduling();


Be sure that you're in the usrp group, and that
/etc/security/limits.conf contains this line:

@usrp  - rtprio 50


If you edit /etc/security/limits.conf I'm pretty sure you need to
reboot to get it to take effect.

Eric