Re: [bgl-discuss] gdb server on bgl inquiry

[Kamil Iskra <iskra@xxxxxxxxxxx>]

On Tue, Jan 31, 2006 at 15:42:00 -0600, Yaakoub El Khamra wrote:

> I am a cactuscode developer (www.cactuscode.org) working on porting 
> physics modules to bluegene. I am wondering if anybody has had recent 
> experience debugging applications on bgl using the gdb server. The 
> system admins have been kind enough to provide access to a partition and 
> from the mpirun output I can see that the server has been started. I 
> cannot however connect to it using gdb.

What exactly do you mean by "cannot connect"?

I just tried your command with my binary on the same partition, and it
sort-of worked.  It wasn't flawless, but debugging was possible to an
extent.  Differences compared to the manual:

- the gdb got blocked after issuing the "target remote" command
- I pressed enter in the mpirun shell
- program was interrupted before main() and gdb became operational
- I could set a breakpoint on main() and continue

Now, one problem that I had was that single-stepping was constantly giving
me (harmless) "Program received signal SIGINT, Interrupt" messages.  But
manually setting temporary breakpoints and continuing (which is essentially
what single stepping does, if I understand it right) worked.  I could query
and set variables, etc.

> The gdb in question is the one 
> in /usr/bin/gdb (the only one I found actaully),

Yep, same here.  Susan: the manual (App. Development) mentions on p. 74 a
different gdb, which is apparently an optional package and should be
available in
/bgl/BlueLight/ppcfloor/ppc/linux-gnu/bin/powerpc-linux-gnu-gdb.  Do you
know anything about that?  This path is obviously broken, since ppcfloor is
a link pointing inside "ppc", but still...

> my mpirun command is as 
> follows:
> 
> mpirun -partition $PARTITION_NAME -exe 
> '/bgl/home1/sbrandt/trial/Cactus/exe/cactus_Bench_BSSN_PUGH' -cwd 
> /bgl/home1/sbrandt/trial/Cactus -np 2 -start_gdbserver 
> /bgl/BlueLight/ppcfloor/dist/sbin/gdbserver.440 -verbose 4

I used essentially the same line, but with a single process and verbosity
level 1.

Kamil

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