I am currently testing with standard tcp RPI device, with a view
to using gm/ib at some point.
I have tried running on both Linux 2.6(SLES9) and 2.4(SLES8).
Not sure I can pre-fork jobs as I need to make sure it is only
the master MPI process that forks (and to do this I would need to
MPI_Init/MPI_Comm_rank...).
Can't really mpirun additional processses as they are non-MPI
third-party programs which use their own communication protocol.
Thanks anyway for your help.
Jeff Squyres wrote:
>I have a guess as to what is happening, but it depends on your
>situation. Are you using the gm or ib RPI devices (which is why you
>say you need the memory manager)?
>
>What OS are you running on? If it's Linux, is it 2.4 or 2.6?
>
>I should say that technically, MPI does not guarantee that fork will
>work. Indeed, gm and ib apps may not even guarantee that fork works
>properly (it's been a while since I've checked; I don't know whether
>they currently support it or not). Hence, you might have larger
>problems than LAM's memory manager, and we can't really help you. :-\
>
>An alternate approach might be to pre-fork jobs (i.e., before
>MPI_INIT), similar to what Apache does, and then communicate with them
>(potentially via pipes) when you need to use them.
>
>Or perhaps you can mpirun all the additional processes that you need,
>and simply have the extras blocking in an MPI_RECV waiting for
>instructions.
>
>Are any of these possible?
>
>
>
>On Jun 30, 2005, at 7:36 AM, Philip Mason wrote:
>
>
>
>>I am trying to run a simple program (np=2) using LAM 7.1.1
>>on Linux. The parent program spawns(forks) a new process
>>and then performs a few malloc/putenvs. However, this
>>forked-process dies inexplicably in one of the calls to malloc.
>>
>>I am using simple LAM setup and have tried on various linux
>>machines including SLES8(AMD64), RH72(IA32).
>>
>>I have tried to run with LAM configured with memory manager off
>>(i.e. --with-memory-manager=none) and this seems to fix the problem.
>>However, I do want the memory-manager to be activated.
>>
>>
>
>
>
--
----------------------------------------
Phil Mason
Software Development Engineer
Ricardo Consulting Engineers Ltd
Email - Philip.Mason_at_[hidden]
Tel: 01273 794914
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