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Subject: Re: [OMPI users] SIGPIPE handling?
From: Ralph Castain (rhc_at_[hidden])
Date: 2010-11-25 10:34:36


After digging around a little, I found that you must be using the OMPI devel trunk as no release version contains this code. I also looked to see why it was done, and found that the concern was with an inadvertent sigpipe that can occur internal to OMPI due to a race condition.

So I modified the trunk a little. We will ignore the first few sigpipe errors we get, but will then abort with an appropriate error.

HTH
Ralph

On Nov 24, 2010, at 5:08 PM, Jesse Ziser wrote:

> Hello,
>
> I've noticed that OpenMPI does not seem to detect when something downstream of it fails. Specifically, I think it does not handle SIGPIPE or pass it down to its young, but it still prints an error message every time it occurs.
>
> For example, running a command like this:
>
> mpirun -np 1 ./mpi-cat </dev/zero | dd bs=1 count=1 >/dev/null
>
> (where mpi-cat is just a simple program that initializes MPI and then copies its input to its output) hangs after the dd quits, and produces an eternity of repetitions of this error message:
>
> [[35845,0],0] reports a SIGPIPE error on fd 13
>
> I am unsure whether this is the intended behavior, but it certainly seems unfortunate from my persepective. Is there any way to make it exit nicely, preferably with a single error, whenever what it's trying to write to doesn't exist anymore? I think I could even submit a patch to make it quit on SIGPIPE, if it is agreed that that makes sense.
>
> Here's the source for my mpi-cat example:
>
> #include <stdio.h>
>
> #include <mpi.h>
>
> int main (int iArgC, char *apArgV [])
> {
> int iRank;
>
> MPI_Init (&iArgC, &apArgV);
>
> MPI_Comm_rank (MPI_COMM_WORLD, &iRank);
>
> if (iRank == 0)
> {
> while(1)
> if(putchar(getchar()) < 0)
> break;
> }
>
> MPI_Finalize ();
>
> return (0);
> }
>
>
> Thank you,
>
> Jesse Ziser
> Applied Research Laboratories:
> The University of Texas at Austin
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