[mythtv] Debugging of mythbackend

[Emlyn.Bolton at nokia.com]

Hi,

I recently upgraded to 0.16, but built from fresh on Gentoo for a couple of other reasons.  Since I did this, I've frequently found mythbackend to be hogging 100% of my CPU when it should really be idle i.e. no transcoding going on.  I wanted to run the backend under gdb to figure out what it's actually doing, but this is proving to be somewhat problematic.  
I do this:

media root # gdb /usr/bin/mythbackend
GNU gdb 6.0
Copyright 2003 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain 
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu"...Using host libthread_db 
library "/lib/libthread_db.so.1".

(gdb) run
Starting program: /usr/bin/mythbackend
warning: Unable to find dynamic linker breakpoint function.
GDB will be unable to debug shared library initializers
and track explicitly loaded dynamic code.
Starting up as the master server.
2004-09-21 12:47:17 mythbackend: MythBackend started as master server

Program received signal SIG32, Real-time event 32.
0x413c3974 in pthread_getconcurrency () from /lib/libpthread.so.0
(gdb) kill
Kill the program being debugged? (y or n) y
(gdb) quit

So I then did:

media root # ld /lib/libthread_db.so.1
ld: warning: cannot find entry symbol _start; not setting start address
/lib/libthread_db.so.1: undefined reference to `ps_pdwrite'
/lib/libthread_db.so.1: undefined reference to `ps_pglobal_lookup'
/lib/libthread_db.so.1: undefined reference to `ps_lsetfpregs'
/lib/libthread_db.so.1: undefined reference to `ps_getpid'
/lib/libthread_db.so.1: undefined reference to `ps_lsetregs'
/lib/libthread_db.so.1: undefined reference to `ps_pdread'
/lib/libthread_db.so.1: undefined reference to `ps_lgetfpregs'
/lib/libthread_db.so.1: undefined reference to `ps_lgetregs'
media root #

and find out (through google) that gdb should provide these exported functions.

Sorry for being new to the linux debugging game, but what do I do in this case?  Help much appreciated!!

Emlyn Bolton