[MPICH] nemesis in a threaded code

[chong tan]

randomly, a package sent by MPI_Send disappear, the reciever ended up
waiting for a package that never show up.  This does not happen when the
apllication is not threaded.

I have completed the test using --enable-threads=funnel.  The main thread is
the only one calling MPI.  (actually, only the master of all MPI processes are
multi-threaded).  It works much better, the horror is, it drops packages once 
in many runs.  So, nemesis is pretty much useless for any threaded application.

BTW, the package dropping usually happen after more than 30,000,000 calls
to MPI_Send and MPI_Recv.

Any suggestion to debug this ?

thanks
tan



----- Original Message ----
From: Darius Buntinas <buntinas at mcs.anl.gov>
To: chong tan <chong_guan_tan at yahoo.com>
Cc: mpich-discuss at mcs.anl.gov
Sent: Wednesday, April 11, 2007 2:22:39 PM
Subject: Re: [MPICH] nemesis in a threaded code


Hmm, what do you mean by "dropping packages"?  What symptoms are you seeing?

Darius

chong tan wrote:
> that is what I thought too.  But without using --enable-threads, nemesis is
> dropping packages randomly in a threaded env.  I will rebuild with
> --enable-threads=funnel to see what happen.
>  
> tan
> 
> 
>  
> ----- Original Message ----
> From: Darius Buntinas <buntinas at mcs.anl.gov>
> To: chong tan <chong_guan_tan at yahoo.com>
> Cc: mpich-discuss at mcs.anl.gov
> Sent: Wednesday, April 11, 2007 1:07:04 PM
> Subject: Re: [MPICH] nemesis in a threaded code
> 
> Nemesis only supports thread_single.  However, as long as you ensure
> that only one thread is making MPI calls, it should work fine.
> 
> Darius
> 
> chong tan wrote:
>  > with MPI calls done by the main thread, nemesis is dropping packages.  
>  > Should I build MPICH
>  > using --enable-threads=funneled ?
>  >  
>  > thanks
>  > tan
>  >  
>  >
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