Re: [Discuss-gnuradio] Long-running app getting into trouble

[Eric Blossom]

On Sun, May 30, 2010 at 11:26:34PM -0400, Marcus D. Leech wrote:
> I have a long-running Gnu Radio application--my VLF sid receiver.  It
> seems to "wedge" after a few days
>   of flawless operation.
> 
> The application uses an audio source, and an audio sink, but usually the
> source and sink are on
>   two different sound cards.
> 
> The application uses a number of WxGUI widgets, and was generated using
> GRC.  I don't see any evidence
>   for a memory leak, the app reaches stable virtual and resident-set
> sizes fairly quickly, and they don't change.
> 
> There's no evidence for a file-descriptor leak (checked /proc/XXXX for
> each of the 3 processes involved, and
>   everything looks good).
> 
> No kernel error messages (and this application behaves this way across
> different distributions of
>   Linux--both Ubuntu and Fedora show this problem).
> 
> Next time it happens, I'll force a core dump, and see if I can see where
> it's getting hung.
> 
> But it's most puzzling, and a little worrying.  I really need this app,
> and ones like it to run
>   essentially indefinitely, doing what they do.  If anyone has any kind
> of clue, and wants the
>   code (most of it produced in GRC), please let me know.
> 
> Cheers(?)
> Marcus

When it wedges, does it continue to consume CPU, or does it appear to
be blocked?

When it wedges, you should be able to attach to it with gdb.
Run gdb on /usr/bin/python, then attach it to the PID that corresponds
to your app.

(gdb) attach <pid>
(gdb) thread apply all bt

will generate a backtrace for all threads.

Eric