v4.1.x: libnbc fix for iallreduce count*extent overflowing int #10094
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In the libnbc iallreduce ring algorithm at -np 4, if the datatype is
MPI_LONG_LONG of 8bytes and a count is used like 1.5 billion so the
total bytes is 12Gb, the offsets for some of the iterations were going
negative.
gist for testcase:
https://gist.github.com/markalle/61e05fed6de4cd201d5e7d22b0c175a1
% mpicc -o x iallreduce_overflow.c
% mpirun -np 4 --mca coll_libnbc_iallreduce_algorithm 1 ./x 12000000000
The testcase picks a random number of bytes for the allreduce buffer if one
isn't specified on the command line.
Signed-off-by: Mark Allen <markalle@us.ibm.com>
(cherry picked from commit b8d6b6b)
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bot:mellanox retest |
jsquyres
changed the title
awlauria
approved these changes
Mar 14, 2022
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In the libnbc iallreduce ring algorithm at -np 4, if the datatype is
MPI_LONG_LONG of 8bytes and a count is used like 1.5 billion so the
total bytes is 12Gb, the offsets for some of the iterations were going
negative.
gist for testcase:
https://gist.github.com/markalle/61e05fed6de4cd201d5e7d22b0c175a1
% mpicc -o x iallreduce_overflow.c
% mpirun -np 4 --mca coll_libnbc_iallreduce_algorithm 1 ./x 12000000000
The testcase picks a random number of bytes for the allreduce buffer if one
isn't specified on the command line.
Signed-off-by: Mark Allen markalle@us.ibm.com
(cherry picked from commit b8d6b6b)