Re: [Discuss-gnuradio] QT GUI Segmentation Fault

[Michael Rahaim]

Just a follow up on this - I was able to resolve the issue with the following modifications in the volk_config file:

before:          volk_32fc_32f_multiply_32fc a_avx generic

changed to:   volk_32fc_32f_multiply_32fc generic generic

before:          volk_32fc_deinterleave_64f_x2 a_avx u_avx

changed to:   volk_32fc_deinterleave_64f_x2 generic u_avx

While I'm happy to have it working again, I don't exactly know what this modification actually does. If anyone with knowledge of the volk library can give me a quick bit of info about what these modifications are actually doing and / or why this would resolve the segfault issue, it would ease my mind a bit.

Thanks,

-Mike

On Thu, Oct 30, 2014 at 11:13 AM, Michael Rahaim <address@hidden> wrote:

Hi all,

I recently installed GNURadio on two laptops (installation via PYBOMBs) and everything has been running fine for a few weeks; but I'm suddenly running into issues with QT GUI on one of the laptops. I wasn't sure what the issue was originally, but after narrowing it down I'm able to see the problem with a simple flow graph:

signal source -> throttle -> QT GUI Sink

Starting with a blank slate in GRC and building the flow graph works fine on one device; but the same flow graph on the second laptop opens and closes immediately with return code -11. If I run the python code outside of GRC, I get the segmentation fault.

I was looking for a solution and I came across bug 645 (http://gnuradio.org/redmine/issues/645) that was resolved in 3.7.3, but these laptops have 3.7.6 (git-133-gd814810) installed.

I noticed that the bug report mentions the avx volk kernel as the issue and both of my machines indicate that they're using volk machine avx_64_mmx. I also ran volk_profile and changed "volk_32fc_32f_multiply_32fc a_avx generic" to "volk_32fc_32f_multiply_32fc generic generic" as indicated in the bug report, but I still see the problem.

To be honest, I don't really know how the volk library works and I'm not sure what else I should try changing. If anybody has suggestions, it would be greatly appreciated.

Thanks in advance,

-Mike