[mpich-devel] MPI_Bsend under MPIU_THREAD_GRANULARITY_PER_OBJECT

[Bob Cernohous]

Patches could be tricky because I'm even seeing intermittent (and 
different) failures on our 'legacy' libraries which are not per-obj but 
use the big lock.  So there's probably more than one problem here.

Abort(1) on node 3 (rank 3 in comm 1140850688): Fatal error in MPI_Bsend: 
Internal MPI error!, error stack:
MPI_Bsend(181)..............: MPI_Bsend(buf=0x19c8a06da0, count=1024, 
MPI_CHAR, dest=0, tag=0, MPI_COMM_WORLD) failed
MPIR_Bsend_isend(226).......: 
MPIR_Bsend_check_active(456): 
MPIR_Test_impl(65)..........: 
MPIR_Request_complete(234)..: INTERNAL ERROR: unexpected value in case 
statement (value=0)


Bob Cernohous:  (T/L 553) 507-253-6093

BobC at us.ibm.com
IBM Rochester, Building 030-2(C335), Department 61L
3605 Hwy 52 North, Rochester,  MN 55901-7829

> Chaos reigns within.
> Reflect, repent, and reboot.
> Order shall return.




From:   Dave Goodell <goodell at mcs.anl.gov>
To:     devel at mpich.org, 
Date:   04/25/2013 11:14 AM
Subject:        Re: [mpich-devel] MPI_Bsend under 
MPIU_THREAD_GRANULARITY_PER_OBJECT
Sent by:        devel-bounces at mpich.org



The Bsend paths almost certainly have not been protected correctly. 
Patches to fix the issue are most welcome.

-Dave

On Apr 25, 2013, at 10:49 AM CDT, Bob Cernohous <bobc at us.ibm.com> wrote:

> Start by saying that I have not been involved in the nitty gritty of the 
per-object locking design. 
> 
> What protects the attached buffer/data structures/request when doing 
multithreaded MPI_Bsend()'s?  All I see in the code path is a (no-op) 
MPIU_THREAD_CS_ENTER(ALLFUNC,). 
> 
> I have a customer test in which the threads seem to be walking all over 
the request around: 
> 
> 
/bgusr/bobc/bgq/comm/lib/dev/mpich2/src/mpid/pamid/include/../src/mpid_request.h:259 

> 0000000001088c0c MPIR_Request_complete 
> /bgusr/bobc/bgq/comm/lib/dev/mpich2/src/mpi/pt2pt/mpir_request.c:87 
> 000000000106e874 MPIR_Test_impl 
>         /bgusr/bobc/bgq/comm/lib/dev/mpich2/src/mpi/pt2pt/test.c:62 
> 00000000010188f0 MPIR_Bsend_check_active 
> /bgusr/bobc/bgq/comm/lib/dev/mpich2/src/mpi/pt2pt/bsendutil.c:455 
> 0000000001018dc0 MPIR_Bsend_isend 
> /bgusr/bobc/bgq/comm/lib/dev/mpich2/src/mpi/pt2pt/bsendutil.c:226 
> 0000000001008734 PMPI_Bsend 
>         /bgusr/bobc/bgq/comm/lib/dev/mpich2/src/mpi/pt2pt/bsend.c:163 
> 00000000010009c0 00000012.long_branch_r2off.__libc_start_main+0 
>         :0 
> 000000000130cbc0 start_thread 
> 
> eg. (fprinting from MPIU_HANDLE_LOG_REFCOUNT_CHANGE) 
> 
> stderr[8]: set 0x15f8048 (0xac0000ff kind=REQUEST) refcount to 2 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to 1 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to 0 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -1 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -2 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -3 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -4 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -5 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -6 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -7 
> stderr[8]: decr 0x15f8048 (0xac0000ff kind=REQUEST) refcount to -8 
> 
> 
> Bob Cernohous:  (T/L 553) 507-253-6093
> 
> BobC at us.ibm.com
> IBM Rochester, Building 030-2(C335), Department 61L
> 3605 Hwy 52 North, Rochester,  MN 55901-7829
> 
> > Chaos reigns within.
> > Reflect, repent, and reboot.
> > Order shall return.


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