# Ctrlport-monitor: radio.get threw exception (math domain error)

**URL:** <https://www.ruby-forum.com/t/ctrlport-monitor-radio-get-threw-exception-math-domain-error/240087>\
**Category:** GNU Radio\
**Created:** [March 26, 2014, 9:29pm UTC](https://www.ruby-forum.com/t/ctrlport-monitor-radio-get-threw-exception-math-domain-error/240087 "2014-03-26T21:29:32Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [March 26, 2014, 9:29pm UTC](https://www.ruby-forum.com/t/ctrlport-monitor-radio-get-threw-exception-math-domain-error/240087/1 "2014-03-26T21:29:32Z")

</div>

I get the following error when trying to the run gr-perf-monitorx  
against a  
flow graph that has an RTL\_SDR radio as the source. I recompiled both  
rtl\_sdr and gr\_osmosdr after enabling performance counters in gnuradio.

The odd thing is that it works fine when I do not have an RTL\_SDR radio  
attached. In that instance gr-osmosdr simply attaches a null source  
instead. This seems to point to the RTL\_SDR source. Has anyone  
succesfully  
used gr-perf-monitorx with a RTL\_SDR source?

Thanks

Luke

PS - also just in case anyone else tries, ‘perf top’ doesn’t work in a  
VM…

---

<div class="post-metadata">

**Author:** ![hagus](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/9de053/32.png) [@hagus](https://www.ruby-forum.com/u/hagus)\
**Post date:** [April 11, 2014, 10:12pm UTC](https://www.ruby-forum.com/t/ctrlport-monitor-radio-get-threw-exception-math-domain-error/240087/2 "2014-04-11T22:12:17Z")

</div>

On Wed, Mar 26, 2014 at 4:28 PM, Luke B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Luke
> 
> PS - also just in case anyone else tries, ‘perf top’ doesn’t work in a  
> VM…

Luke,

This gut buried in my inbox. Any updates on your success with this? Are  
you  
running into this on a VM? It might be something related to that,  
anyways.

Tom

---

<div class="post-metadata">

**Author:** ![hagus](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/9de053/32.png) [@hagus](https://www.ruby-forum.com/u/hagus)\
**Post date:** [April 11, 2014, 10:28pm UTC](https://www.ruby-forum.com/t/ctrlport-monitor-radio-get-threw-exception-math-domain-error/240087/3 "2014-04-11T22:28:50Z")

</div>

Not a problem - It was under a VM, so that is probably what was causing  
it.  
I ran it at home on bare metal with a HackRF and didn’t have any issues.