Thanks for clarification. I see type and filetype specification in the standard mention "monotonically nondecreasing" constraint.

I mean etype and filetype. -Pramod On Wed, Aug 23, 2017 at 3:07 AM, Latham, Robert J. <[email protected]> wrote:

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On Tue, 2017-08-22 at 22:27 +0000, Thakur, Rajeev wrote:

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Yes, displacements for the filetype must be in “monotonically nondecreasing order”.

... which sounds pretty restrictive, but there is no constraint on memory types. Folks work around this by shuffling the memory addresses to match the ascending file offsets.

==rob

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Rajeev

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On Aug 22, 2017, at 3:05 PM, pramod kumbhar <pramod.s.kumbhar@gmail .com> wrote:

Hi Rob,

Thanks! Below is not exactly same issue/error but related :

While constructing derived datatype (filetype used for set_view), do we need displacements / offsets to be in ascending order? I mean, suppose I am creating derived datatype using MPI_Type_create_hindexed (or mpi struct) with length/displacements as:

blocklengths[0] = 8; blocklengths[1] = 231670; blocklengths[2] = 116606;

displacements[0] = 0; displacements[1] = 8; displacements[2] = 231678;

Above displacements are in ascending order. Suppose I shuffle order bit:

blocklengths[0] = 8; blocklengths[1] = 116606; blocklengths[2] = 231670;

displacements[0] = 0; displacements[1] = 231678; displacements[2] = 8;

It's still the same but while specifying block-lengths/offsets I changed the order. (resultant file will have data in different oder but that's ignored here) Isn't this a valid specification? This second example results in a segfault (in ADIO_GEN_WriteStrided / Coll).

I quickly wrote attached program, let me know if I have missed anything obvious here.

Regards, Pramod

p.s. you can compile & run as:

Not working => mpicxx test.cpp && mpirun -n 2 ./a.out Working =>. mpicxx test.cpp -DUSE_ORDER && mpirun -n 2 ./a.out

On Tue, Aug 22, 2017 at 5:25 PM, Latham, Robert J. <[email protected] v> wrote: On Mon, 2017-08-21 at 17:45 +0200, pramod kumbhar wrote:

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Dear All,

In one of our application I am seeing following error while using collective call MPI_File_write_all :

Error in ADIOI_Calc_aggregator(): rank_index(1) >= fd->hints-

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cb_nodes (1) fd_size=102486061 off=102486469

Non collective version works fine.

While looking at callstack I came across below comment in mpich- 3.2/src/mpi/romio/adio/common/ad_aggregate.c :

/* we index into fd_end with rank_index, and fd_end was allocated to be no * bigger than fd->hins->cb_nodes. If we ever violate that, we're * overrunning arrays. Obviously, we should never ever hit this abort */ if (rank_index >= fd->hints->cb_nodes || rank_index < 0) { FPRINTF(stderr, "Error in ADIOI_Calc_aggregator(): rank_index(%d) >= fd->hints->cb_nodes (%d) fd_size=%lld off=%lld\n", rank_index,fd->hints->cb_nodes,fd_size,off); MPI_Abort(MPI_COMM_WORLD, 1); }

I am going to look into application and see if there is an issue with offset overflow. But looking at above comment ("Obviously, we should never ever hit this abort ") I thought should ask if there is any obvious thing I am missing.

that's my comment. The 'rank_index' array is allocated based on the 'cb_nodes' hint. I definitely would like to know more about how the code is manipulating rank_index, cb_nodes, and fd_end .

If there is a reduced test case you can send me, that will be a huge help.

==rob

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Regards, Pramod

p.s. I will provide reproducer after looking into this more carefully. _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

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