MPI debugging support in GDB?

MPI debugging support in GDB?

[Daniel Qarras]

Hi!

What is the current status for debugging MPI applications with GDB? If
this is already possible/doable is there some documentation available?
If this not possible are there any plans to implement this?

We use a small cluster to run MPI applications and otherwise the system
consists only of free (beer/speech) software but to me it seems that
proprietary and pricy debuggers are needed to debug MPI application
(like TotalView or PGI CDK). There are several open software MPI
libraries available (like OpenMPI and MVAPICH) but of course a debugger
is needed every now and then.

Thanks!




       
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Re: MPI debugging support in GDB?

[Daniel Jacobowitz]

On Sat, Sep 29, 2007 at 07:58:11AM -0700, Daniel Qarras wrote:
> Hi!
> 
> What is the current status for debugging MPI applications with GDB? If
> this is already possible/doable is there some documentation available?
> If this not possible are there any plans to implement this?

Nothing special and no plans that I'm aware of.

-- 
Daniel Jacobowitz
CodeSourcery

Re: MPI debugging support in GDB?

[Daniel Qarras]

> > If you know, could you say something about what kind of support would be
> > needed?  Even that would help a bit, I think.
> 
> I think that for full and transparent support, we'd need to start with
> being able to debug multiple (remote) targets simultaneously?  GDB can't
> do that currently --- it can only debug multiple processes running on
> the same host.

Yes, I think this is a hard requirement. I'm also pretty sure that supporting code would be needed for each MPI library implementation (their might have something comparable to libthread_db/nptl_db). OpenMPI is the most prominent open source MPI implementation today, its page might give some additional clues:

http://www.open-mpi.org/faq/?category=debugging

Thanks!

Re: MPI debugging support in GDB?

[Pedro Alves]

On Wednesday 14 October 2009 15:40:45, Tom Tromey wrote:
> >>>>> "Sérgio" == Sérgio Durigan Júnior <sergiodj@linux.vnet.ibm.com> writes:
> 
> Tom> I haven't heard of anybody working on MPI support for GDB.
> 
> Sérgio> Last year, I was starting a work in order to implement such a
> Sérgio> support on GDB.  However, due to internal reasons, I had to quit
> Sérgio> this and start another task.  Unfortunately, I only spent a few
> Sérgio> days studying MPI and did not have the chance to create an
> Sérgio> opinion about how difficult it would be to make GDB support it.
> 
> If you know, could you say something about what kind of support would be
> needed?  Even that would help a bit, I think.

I think that for full and transparent support, we'd need to start with
being able to debug multiple (remote) targets simultaneously?  GDB can't
do that currently --- it can only debug multiple processes running on
the same host.

-- 
Pedro Alves

Re: MPI debugging support in GDB?

[Tom Tromey]

>>>>> "Sérgio" == Sérgio Durigan Júnior <sergiodj@linux.vnet.ibm.com> writes:

Tom> I haven't heard of anybody working on MPI support for GDB.

Sérgio> Last year, I was starting a work in order to implement such a
Sérgio> support on GDB.  However, due to internal reasons, I had to quit
Sérgio> this and start another task.  Unfortunately, I only spent a few
Sérgio> days studying MPI and did not have the chance to create an
Sérgio> opinion about how difficult it would be to make GDB support it.

If you know, could you say something about what kind of support would be
needed?  Even that would help a bit, I think.

Tom

Re: MPI debugging support in GDB?

[Sérgio Durigan Júnior]

On Tuesday 13 October 2009, Tom Tromey wrote:
> >>>>> "Daniel" == Daniel Qarras <dqarras@yahoo.com> writes:
> 
> Daniel> Now that GDB 7.0 with multi-process support is out (thanks to
> Daniel> everyone involved!) I started to wonder does it pave way to MPI
> Daniel> support in GDB in any way? I would presume it to be a
> Daniel> prerequisite but does anyone happen to know what it would take
> Daniel> in practise to make that happen (let's say, with OpenMPI)?
> 
> I haven't heard of anybody working on MPI support for GDB.

Last year, I was starting a work in order to implement such a support on GDB.  
However, due to internal reasons, I had to quit this and start another task.  
Unfortunately, I only spent a few days studying MPI and did not have the 
chance to create an opinion about how difficult it would be to make GDB 
support it.

-- 
Sérgio Durigan Júnior
Linux on Power Toolchain - Software Engineer
Linux Technology Center - LTC
IBM Brazil

Re: MPI debugging support in GDB?

[Tom Tromey]

>>>>> "Daniel" == Daniel Qarras <dqarras@yahoo.com> writes:

Daniel> Now that GDB 7.0 with multi-process support is out (thanks to
Daniel> everyone involved!) I started to wonder does it pave way to MPI
Daniel> support in GDB in any way? I would presume it to be a
Daniel> prerequisite but does anyone happen to know what it would take
Daniel> in practise to make that happen (let's say, with OpenMPI)?

I haven't heard of anybody working on MPI support for GDB.

I have heard a few requests for this, but I know very little about MPI,
so I don't even know what would be needed.

Tom

Re: MPI debugging support in GDB?

[Daniel Qarras]

Hi!

Now that GDB 7.0 with multi-process support is out (thanks to everyone involved!) I started to wonder does it pave way to MPI support in GDB in any way? I would presume it to be a prerequisite but does anyone happen to know what it would take in practise to make that happen (let's say, with OpenMPI)?

--- On Sat, 9/29/07, Daniel Qarras <dqarras@yahoo.com> wrote:

> From: Daniel Qarras <dqarras@yahoo.com>
> Subject: MPI debugging support in GDB?
> To: gdb@sourceware.org
> Date: Saturday, September 29, 2007, 10:58 AM
> 
> What is the current status for debugging MPI applications with GDB? If
> this is already possible/doable is there some documentation
> available? If this not possible are there any plans to implement
> this?

Thanks!