Re: Improving GDB for multicore and embedded system!

[Ramana Radhakrishnan <ramana dot radhakrishnan at celunite dot com>]

Hi,

On Fri, 2007-03-02 at 08:54 -0500, Daniel Jacobowitz wrote:
> On Fri, Mar 02, 2007 at 10:08:55AM +0100, Denis PILAT wrote:
> > Today multicore debugging means multiple instance of gdb running at the 
> > same time. I don't know how possible it is to enhance gdb so that it can 
> > handle multiple programs running on different architecture.
> > I guess Daniel should have a good vision on that.
> 
> No one has ever convinced me that there's a good reason to do this,
> rather than wire up things like DSF to drive multiple GDB's, if the
> cores are not all running the same architecture and program image.  If
> they are, we generally present them as threads, and that works very
> well.
> 
> However, I have relatively little experience with non-symmetric
> multicore debugging - I have a board lab at home but it doesn't
> include any multicore targets, and we haven't done much with them at
> my job, either.  I'm always interested in learning more about new
> debugging models, or having an opportunity to do work on them.

In an earlier incarnation,  we played with getting debug working across
2 different targets ( gosh! nearly 4 years ago now) - debugging a native
x86 Linux application and the ARM Linux kernel over kgdb within the same
session. It worked ok for a prototype but then we could never get around
to doing more with it because of resource constraints and the lack of a
genuine debug use case on such a target. Getting this demo'd on a board
was a problem due to the lack of open gdb ports / JTAG interfaces for
some DSP's that were available with such SOC's then .

Another problem is the programming model on multi-cores , it varies
between platforms quite a bit - you could have a statically linked
executable with all the object files for the different cores on it built
in together - or you can have Linux apps running on something like an
ARM and a DSP application loaded separately. As you once put it in an
earlier thread -  getting the UI aspects right from the CLI as well from
MI are among the biggest challenges. 


We've had some other discussions on this list sometime in 2005. 

http://sourceware.org/ml/gdb/2005-09/msg00180.html

Don't know if you have seen them -


There is always hope that sometime someday we'll be able to do something
about this . I'll watch out for that -

My 10 paise. HTH.

-- 
cheers
Ramana

Ramana Radhakrishnan
GNU Tools
Celunite Inc (www.celunite.com)
Open Mobile Linux Platforms