PETSC debugger

[Ryan Yan]

Thanks, Jed. Please see reply below.


On Mon, Jul 20, 2009 at 3:17 PM, Jed Brown <jed at 59a2.org> wrote:

> Ryan Yan wrote:
> > My X server set up may be messed up somehow. Same error as before.
>
> Using screen bypasses X, so that seems an unlikely candidate.
>
> > After I creat a new session using,
> > vyan2000 at vyan2000-linux
> :~/local/PPETSc/petsc-2.3.3-p15/src/ksp/ksp/examples/tutorials/ttt2$
> > screen -S sdebug
> >
> > Still errors.
>
> No errors at this point though, right?
>

Yes, you are right. There is no error at this point.


>
> > vyan2000 at vyan2000-linux
> :~/local/PPETSc/petsc-2.3.3-p15/src/ksp/ksp/examples/tutorials/ttt2$
> > mpirun -n 4 ./rpisolve -start_in_debugger -debug_terminal "screen -S
> sdebug
> > -X screen"
> > [0]PETSC ERROR: PETSC: Attaching gdb to ./rpisolve on pid 9758 on
> > vyan2000-linux
> > [1]PETSC ERROR: PETSC: Attaching gdb to ./rpisolve on pid 9755 on
> > vyan2000-linux
> > [3]PETSC ERROR: PETSC: Attaching gdb to ./rpisolve on pid 9757 on
> > vyan2000-linux
> > [2]PETSC ERROR: PETSC: Attaching gdb to ./rpisolve on pid 9756 on
> > vyan2000-linux
> >
> > The number of the screen for gdb is not equal to the number of
> > processes.(Mostly, less than), as you can see in the following "bottom
> > margin" of my screen session.
>
> Are there *ever* more sessions than the number of processes?


 No.


> Are there ever the same number?


 Yes, some time. But the error information *is* always there.


>  Is there any consistency to which process is
> missing?


I do not how to check which process is missing... Sorry, I can not answer
this question.


> The output above indicates that the debugger is being run and,
> from the perspective of PetscAttachDebugger, the operation was
> successful.


I agree with you.


>  I have seen this behavior (one missing debug session) on a
> couple occasions, but it wasn't reproducible so I couldn't debug it.


I am using Ubuntu Gnome, maybe the error on this specific linux distribution
is reproducible (It may takes you a while). One of my colleague also have
the same error, she is using a same linux distribution as mine.

vyan2000 at vyan2000-linux:~/local/PPETSc/petsc-2.3.3-p15/src/ksp/ksp/examples/tutorials/ttt2$
uname -a
Linux vyan2000-linux 2.6.24-24-generic #1 SMP Tue Jul 7 19:46:39 UTC 2009
i686 GNU/Linux

vyan2000 at vyan2000-linux:~/local/PPETSc/petsc-2.3.3-p15/src/ksp/ksp/examples/tutorials/ttt2$
lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 8.04.3 LTS
Release:        8.04
Codename:       hardy



>  If this continues to be a problem, I recommend attaching the debugger
> yourself (put "set breakpoint pending on" and "break PetscError" in your
> .gdbinit or run with -on_error_abort).
>

I will try it. But I do not have any experience of attaching the debugger to
something else. Any pointer to a *reference*?

Yan





>
> Jed
>
>
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