Re: [Discuss-gnuradio] USRP underrun

[Eric Blossom]

On Tue, Aug 01, 2006 at 08:26:58PM -0400, Lee Patton wrote:
> I see a single USRP underrun (uU) about four out of five times that my
> application starts.  My transmit work() routine couldn't be simpler: a
> for-loop that moves data from a local buffer to the output buffer.  So,
> I don't think I can scale it back or anything.
> 
> Is there anything I can do to avoid these uU at startup?  Does anyone
> know what might be causing them? Unfortunately my application can't
> tolerate any under/overruns.
> 
> Thanks,
>  -Lee

Have you tried enabling real time scheduling?
You'll need to be running as root or have CAP_SYS_NICE for it to work.

See gnuradio-examples/python/gmsk2/tunnel.py

    # Attempt to enable realtime scheduling
    r = gr.enable_realtime_scheduling()
    if r == gr.RT_OK:
        realtime = True
    else:
        realtime = False
        print "Note: failed to enable realtime scheduling"


Eric