[MPICH] How do I dump a core under MPICH-2?

[Gus Correa]

Hello Jean-Marc Saffroy ( and mpich-discuss list).

Thank you for your advice on how to play safe with coredumpsize!
I removed that line from my .tcshrc file.
Your solution produces the same result, but not the same potential side 
effects.

Jean-Marc Saffroy wrote:

> On Tue, 25 Sep 2007, Gus Correa wrote:
>
>> After I inserted the 'limit coredumpsize unlimited' on my .tcshrc,
>> mpiexec propagates this limit to the parallel job execution environment.
>> However, this only happens if I run anything as a tcsh command.
>
>
> Actually you don't "propagate" the limit, rather you reset it to a 
> fixed value (unlimited) in all new tcsh instances.
>
>> By contrast, if I don't explicitly invoke tcsh, I get:
>>
>> 32-pokey% mpiexec -n 1 limit
>> problem with execution of limit  on  pokey:  [Errno 2] No such file 
>> or directory
>
>
> This is because mpiexec/mpd try to run an external command "limit", 
> which does not exist: it's a shell builtin, and it has to be.
>
Yes, I noticed the behavior (error) was quite different from a regular 
tcsh external command.
Now I know why.

>> When I launch it directly from mpiexec no core dump is produced:
>>
>> 66-pokey% mpiexec -n 1 wrong_hellow
>
> [...]
>
>> However, as you clarified, if I launch it as a (tc)shell command, 
>> with "limit coredumpsize unlimit" set,
>> I do get a core dump:
>>
>> 68-pokey% grep coredumpsize ~/.tcshrc
>> limit coredumpsize unlimited
>>
>> 69-pokey% mpiexec -n 1 tcsh -c 'wrong_hellow'
>> Hello world from process 0 of 1
>> Segmentation fault (core dumped)
>
>
> Setting the limit in your tcshrc can be tedious, and some day you may 
> leave it while a big job crashes, which can be painful. For me, a 
> better alternative is to set the limit only for the job you want to 
> debug, eg:
>
> % mpiexec -n 1 tcsh -c 'limit coredumpsize unlimited; wrong_hellow'
>

Merci,
Gus

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Gustavo J. Ponce Correa, PhD - Email: gus at ldeo.columbia.edu
Lamont-Doherty Earth Observatory - Columbia University
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