[petsc-users] PETSC ERROR: Caught signal number 15 Terminate

[Debao Shao]

Hi, Matt:

http://www.mcs.anl.gov/petsc/petsc-as/miscellaneous/petscthreads.html says "PETSc is not currently thread-safe".
And, you said "PETSc allows threads", I was confused, can you explain a little for me?

Thanks a lot.

Debao
________________________________
From: petsc-users-bounces at mcs.anl.gov [mailto:petsc-users-bounces at mcs.anl.gov] On Behalf Of Matthew Knepley
Sent: Saturday, August 06, 2011 11:19 AM
To: PETSc users list
Subject: Re: [petsc-users] PETSC ERROR: Caught signal number 15 Terminate

On Sat, Aug 6, 2011 at 1:34 AM, Debao Shao <Debao.Shao at brion.com<mailto:Debao.Shao at brion.com>> wrote:
Thanks a lot, Jed and Aron.

Do you have ideas for this problem?


But I encounter a new problem, the situation is:

1, the matrix is big, and can be partitioned to several blocks;

2, started several threads to handle each block of matrix;

3, integrated all block matrices together.



Again, the program crashed with reporting:

"[0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range"

Yes, PETSc allows threads, but one of your threads is illegally accessing memory. I suggest using valgrind to track this down.

   Matt


My libpetsc.a is built with option "--with-mpi=0 --with-debugging=0 -with-log=0 -with-info=0".

Will it support this type of multiple threads?

Thanks,
Debao
________________________________
From: petsc-users-bounces at mcs.anl.gov<mailto:petsc-users-bounces at mcs.anl.gov> [mailto:petsc-users-bounces at mcs.anl.gov<mailto:petsc-users-bounces at mcs.anl.gov>] On Behalf Of Jed Brown
Sent: Friday, August 05, 2011 9:26 PM
To: PETSc users list
Subject: Re: [petsc-users] PETSC ERROR: Caught signal number 15 Terminate

On Fri, Aug 5, 2011 at 04:00, Debao Shao <Debao.Shao at brion.com<mailto:Debao.Shao at brion.com>> wrote:

1, I put "PetscInitialize" at the beginning of main, and "PetscInitialize" registers a signal handler to capture "SIGTERM";

2, the problem ran in server side will send SIGTERM to kill all of clients after one stage is done.

3, then, unfortunately, the signal "SIGTERM" is caught by the signal handler installed by "PetscInitialize", and caused to abort.
You can remove the order dependence by running with -no_signal_handler or setting your own signal handler with:

http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-dev/docs/manualpages/Sys/PetscPushSignalHandler.html

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--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener

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