[Discuss-gnuradio] Unresponsive GUI behavior and system instability with USRP2 + WBX module

[Elvis Dowson]

Hi,
      I noticed that the GNU radio's GUI for a simple FM receiver can become 
un-responsive. For example, when trying to run the WFM receiver example, the 
Frequency Slider moves, but the frequency of the station doesn't change. There 
is a Failed message at the bottom left corner of the GUI. 

At times, when it launches, it works fine and doesn't show the audio buffer 
under-run messages, but if I stop and relaunch the same application, I suddenly 
get a whole bunch of audio buffer under-runs. 

Is GNU Radio stable enough? Or are these type of issues common in the current 
release, and needs to be fixed?

For example, I notice that if some internal blocks or computations don't 
correctly align, like if I have a audio input rate of 32051, the system doesn't 
launch, but if I set the audio input rate to 32050, the WFM receiver launches 
(refer to my earlier thread, where I still haven't got the rational resampler 
way of getting the FM receiver to work). See the following thread for the 
example patch to reproduce this behavior  
http://old.nabble.com/USRP2-%2B-WBX%3A-Unable-to-receive-FM-signals-td29176138.html

I'm assuming that the FM receiver example is simple enough. But if the system 
gets bogged down like this with a simple application, what about more complex 
applications like a WiFi transceiver, or HDTV transmitter/receiver applications?

Is this a general behavior that everyone else sees, i.e. GNU Radio being 
unstable and un-responsive at times? 

I have 8 virtual CPU cores allocated to my Linux VMware image, and a dedicated 
ethernet port connected to the USRP2. CPU utilization is still restricted to 2 
CPUs and the load is between 20 to 30 percent for when running the FM receiver 
application. The host computer is a iMac quad-core i7 processor at 2.8 GHz. 
I've allocated 2.5GB RAM to the linux virtual machine.

I would like to know if the system instability and un-responsiveness is 
something specific to my system configuration or if it is related to GNU Radio 
or the USRP2 or the particular firmware that I'm using (txrx_wbx).

Elvis Dowson