[mpich-devel] MPI_Bsend under MPIU_THREAD_GRANULARITY_PER_OBJECT

Thu Apr 25 14:02:59 CDT 2013

Testcase is pretty simple.  I'll keep poking at it myself and look at that 
ticket too.

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.

devel-bounces at mpich.org wrote on 04/25/2013 01:57:35 PM:

> From: Dave Goodell <goodell at mcs.anl.gov>
> To: devel at mpich.org, 
> Date: 04/25/2013 01:58 PM
> Subject: Re: [mpich-devel] MPI_Bsend under 
MPIU_THREAD_GRANULARITY_PER_OBJECT
> Sent by: devel-bounces at mpich.org
> 
> In that case, test programs to help us reproduce this are also welcome.
> 
> There's also always a risk that one of the currently missing ALLFUNC
> critical sections is affecting your user:
> 
> https://trac.mpich.org/projects/mpich/ticket/1797
> 
> -Dave
> 
> On Apr 25, 2013, at 11:38 AM CDT, Bob Cernohous <bobc at us.ibm.com> wrote:
> 
> 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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